1. As outlined in the Statement of Facts, Issues and Contentions submitted by the Registrar's representative, the issues that arise in this application are:
   • Whether there has been a change in the care provided by the applicant as notified on 6 December 2022;
     • If there was a change in care:
       • From what date did the care change?;
       • What are the percentages of care attributable to the applicant and other party from this date?;
       • From what date do these new percentages of care take effect?
   • From what date does the Tribunal's decision come into effect?

1. The law that applies in this case is the Child Support (Assessment) Act 1989 (Cth) ('the Assessment Act') and the Child Support (Registration and Collection) Act 1988 (Cth) ('the Collection Act'). The provisions regarding percentage of care are found in Division 4 of Part 5 of the Assessment Act. Subdivision C of Division 4 of Part 5 of the Assessment Act deals with the provisions relating to the revocation of an existing care percentage determination. In considering the revocation of an existing care determination and the making of a new care determination, I may also have regard to the Child Support Guide ('the Guide') where relevant, so long as what it contains is lawful. However, I am not bound to follow it.[11]
2. In considering whether to revoke an existing care determination, the Assessment Act requires the consideration of whether the parties have had, or are likely to have, a 'pattern of care' for the child during the care period. The care period is such a period as the Registrar considers to be appropriate having regard to all the circumstances.[12] The government policy in this regard, as set out in Chapter 2.2.1 of the Guide, provides that a care period is generally assumed to apply for the subsequent 12‑month period from when the actual care of a child began or changed, however a shorter or longer care period may be appropriate depending upon the specific circumstances. The pattern of care informs the assessment of the 'percentage of care' used in the formula. The pattern and percentage of care will commonly be determined by reference to the number of nights each child spends in the care of each party to the assessment.[13]
3. Once a determination of the care percentages has been made and applied to the assessment, this care determination will continue until the Registrar is informed, or becomes aware, that the care was not occurring or there was a change. If notified of a change, the Registrar must consider whether a change has occurred. If satisfied that there has been a change, then the existing determination of percentage of care must be revoked and another determination of percentage of care made.
4. In determining whether to revoke an existing determination of care and make a new determination, it is necessary to decide under sections 54F, 54G or 54H of the Assessment Act whether the existing care determination must or should be revoked. Once it has been determined that the existing care determination should be revoked, the Registrar must make a new care percentage determination under section 49 or section 50 of the Assessment Act.
5. Section 54H of the Assessment Act only applies if sections 54F and 54G do not apply. Similarly, 54F of the Assessment Act only applies if 54G does not apply. I will therefore firstly consider section 54G of the Assessment Act to determine whether the existing care determination should be revoked under this section, prior to considering 54F and 54H of the Assessment Act.

1. If I determine that the existing percentage of care should be revoked and make another determination of the percentage of care, I will also need to decide the date of effect of any changes to the percentage of care. Whether the objection was lodged within 28 days of the original decision,[14] and whether the application for first review was made within 28 days of the objection decision,[15] will affect the date from which any new percentage of care will apply.
2. In written submissions, the Registrar notes that if I were to set aside or vary the objection decision, I would need to determine whether to make a determination under subsection 95N(2) of the Collection Act. In relation to subsection 95N(2) of the Collection Act, any decision setting aside or varying the objection decision would take effect from the date of the application for review, unless there are special circumstances that prevented the lodging the application for review within time.
3. The Registrar also submits that if I were to make a determination under subsection 95N(2) of the Collection Act, it is necessary to consider whether the decision comes into effect on the date the objection was lodged or from the date of the notification of the change in the percentage of care if I found that there were special circumstances which prevented the mother from lodging the objection within time.
4. The Registrar submits that the entirety of the first review decision, including considering sections 87AA and 95N of the Collection Act, is open to review in these proceedings even though the first review decision did not consider these sections of the Collection Act.[16] I agree with these submissions.

1. The father's oral evidence was that the care had been in accordance with the court orders dated 3 October 2022.[17] The father referred to text messages[18] which evidenced the child being in his care, and his approval of the child staying overnight with friends and also attending a concert with the child (and his other child). The father conceded that there was a three-week period from 16 November 2022 where the child was with the mother but that the child also went back and forth between his home and the mother's during that time. The father stated that he did not keep a care calendar for the period because he thought that the Registrar would rely on what the court order stated regarding the care of the child.
2. The father stated that the court order in relation to the care of the child was not followed, but the child was predominantly in his care. He stated that the child was at his home and that the text messages provided show that the child was living at his home and demonstrated the regularity of his care. The father stated that the child had personal items at both his home and the mother's home and that the child would take a bag of items when going to the mother's home. The father acknowledged that he left Australia for work overseas and was advised that this occurred on 1 April 2023.
3. I note that the mother provided to the Registrar, prior to the objection to the care percentage decision, a statement from a neighbour dated 30 January 2023.[19] This statement recounts that the mother told the neighbour that the child was living with the mother since mid-November. The neighbour further states that they had been to the mother's home and that the child had been living at the premises since 16 November. After the objection was lodged, the mother provided a letter dated 28 November 2023 from a Child Safety Officer which stated that the mother had been providing care since 1 November 2022.[20]
4. The father stated at hearing that Child Safety was not involved with the child until July 2023. On application for second review with the Tribunal, the father provided an email from the Child Safety Officer who wrote the initial letter provided by the mother to the objection officer which stated that the mother reported the dates referred to in the letter indicating that she had been caring for the child from November 2022.

Assessing the evidence as to the pattern of care for the child

1. In considering the evidence before me, I need to reach a conclusion based on 'rationally probative evidence' rather than mere 'suspicion or speculation'.[21] I have considered the care of the child for the period from 1 November 2022 to 31 March 2023, as it is clear from the evidence before me that the care changed from 1 April 2023. I have determined that it is appropriate to consider the care for this period. Weighing the evidence, I am not satisfied that the mother's evidence establishes that the father's care of the child changed from 16 November 2022. The father conceded in his oral evidence that there was a three-week period in November 2022 where the child was with the mother, but his evidence also indicated that during this time he had the child in his care on some days, including at least 16 and 22 November 2022. The father stated that the child went between his home and the mother's home during this period and the following three-week period. I do not consider this three-week period in November 2022 as indicating a change in the pattern of care of the parents.
2. The Registrar's delegate and the AAT on first review have also relied upon the evidence of the Child Safety Officer as third-party evidence of the change in care. However, the subsequent email from the Child Safety Officer provided by the father in this application shows that the information in the letter dated 28 November 2023 was based on the mother's reported care of the child and not on the Child Safety Officer's own observations. In these circumstances, I am not persuaded by this evidence indicating a change in the care of the child. Similarly, the letter in support provided by the mother's neighbour is based on the mother's information as provided to the neighbour. I have not given the evidence of this letter provided by the mother any weight. While the letter observes the child at the mother's home, it does not provide any detail as to the frequency of these observations. It does not assist me in concluding that the care for the child had changed and that the child was no longer in the father's care.
3. The father's evidence was that the child had personal items at both homes and would take a bag to the mother's home when staying with the mother. The father submits that there was no other evidence, apart from the correspondence, provided by the mother. The court orders dated 3 October 2022 show the child in the father's care for 73% and the mother's care for 27% of the time. I am not satisfied that there is sufficient evidence which shows that the mother's care of the child increased from 16 November 2022 as was determined on objection and affirmed on first review by the AAT. Accordingly, as I am not satisfied that the care changed from 16 November 2022, I find that there is no basis for the care to be revoked from this date.

From what date does the Tribunal's decision come into effect?

1. The evidence of the father was that the objection decision notification was sent electronically on 16 December 2023.[22] The application for first review with the AAT was made on 23 January 2024.[23] I am satisfied that the written notification of the decision made on 16 December 2023 was received by the mother and the father on 16 December 2023.[24]
2. The father lodged his application for review with the AAT more than 28 days from the date he was notified of the objection decision. As stated previously in these reasons, section 95N of the Collection Act provides that a review decision will have effect from the date the application for review was made if the application was lodged more than 28 days after the objection decision. However, if there are special circumstances that prevented the person from lodging the application within 28 days, the Tribunal may allow for a longer application period.[25]
3. The father stated that he lodged on 23 January 2024 because he was awaiting information from the Child Safety Officer, but that the response was delayed. He stated that he went back to the Registrar but was then told that he had to apply for review with the AAT. The father confirmed that he had read the letter sent with the objection decision which stated his further appeal rights rested with the AAT but assumed that the Registrar would reconsider the decision once he provided the information. He stated that the mother was provided time to provide information, and that he had assumed extra time would be given to him as well. The father conceded that the evidence from the Child Safety Officer that he was seeking did not prevent him from lodging an application with the AAT, but he thought he needed the information before making the application.
4. The term 'special circumstances' is not defined in the Collection Act. In Gyselman v Gyselman [1991] FamCA 93; (1992) FLC 92-279 ('Gyselman'), the Full Family Court held that for there to be special circumstances, the facts of the case must establish something which is special or out of the ordinary. As submitted by the Registrar, and with which I agree, subsection 95N(2) of the Collection Act requires that there must be a connection between the circumstances and the person's inability to lodge the objection within time.
5. I am not satisfied that there are special circumstances which prevented the father from lodging within 28 days of 16 December 2023, that being the date of notification. Consequently, having found that there are no special circumstances, the date of effect of this decision is the date of the application for review to the AAT, which is 23 January 2024.

1. The Tribunal sets aside the decision under review and substitutes a new decision as follows:
   • That there has been no change in the care of the child from 16 November 2022; and
   • Not to make a determination under subsection 95N(2) of the Child Support (Registration and Collection) Act 1988 with the consequence that the date of effect of the Tribunal's decision is 23 January 2024 (when the application for review was lodged).

[10] Administrative Review Tribunal (Consequential and Transitional Provisions No. 1) Act 2024.

[11] Re Drake and Minister for Immigration and Ethnic Affairs (No 2) (1979) 2 ALD 634; G v MIBP [2018] FCA 1229.

[12] Subparagraph 50(1)(b)(ii) of the Assessment Act.

[13] Section 54A of the Assessment Act and section 2.2.1 of the Guide.

[14] Section 87AA of the Collection Act.

[15] Section 95N of the Collection Act.

[16] See Child Support Registrar v MQMV [2019] FCA 1171.

[18] Text Evidence 3 and 4 provided by the father to the Tribunal.

[21] Minister for Immigration and Ethnic Affairs v Pochi [1980] FCA 85; (1980) 31 ALR 666 at 685.

[24] Per section 14A of the Electronic Transactions Act 1999 (Cth) and section 161 of the Evidence Act 1995 (Cth).