24 No matter how the sentences are viewed, the balance of term exceeded one-third of the non-parole period. If one considers only the non-parole period set in respect of the sentence for the attempted armed robbery, which was 4½ years, the balance of term should not have exceeded 18 months and the total term should have been 6 years. Taking account of the 12 months accumulation, the aggregate total term would then have been 7 years. If one begins with the aggregate sentence, the non-parole period was 5½ years and the balance of term should not have exceeded 22 months, giving a total term of 7 years and 4 months.
25 Obviously, the outcome is the same if one works backwards from the total term. For the aggregate term of 8½ years, the non-parole period should have been 6 years and 4½ months (instead of 5½ years). Working backwards from the 7½ years imposed for the attempted armed robbery gives 5 years and 7½ months (instead of 4½ years). It follows that the structure of the sentence did not, on any analysis, conform to the requirement of s 44(2). The question is whether the departure was intended.
26 It is clear that the Judge was aware that the sentence had to comply with the statutory ratio unless he made a finding of special circumstances. In that context, it is necessary to consider his Honour's remark that he did not propose to do so, but "instead, the simple mathematics of the situation" would dictate some adjustment to the sentence and that the "same mathematics" provided a sufficient period under supervision. It is likely that the mathematics to which his Honour was referring was the impact of partial accumulation. There was no other circumstance or aspect of the sentence that could alter the ratio.
27 On that basis, in my view, the most logical interpretation of the remark is that his Honour thought the sentence he was imposing in respect of the attempted armed robbery conformed to the requirement of the statute, but that the application of that ratio to the aggregate sentence dictated a longer balance of term. That follows from the "simple mathematics" that one third of 5½ years is more than one third of 4½ years (the difference being 4 months).
28 The Crown submitted that it is possible his Honour had in mind the fact that the sentence was accumulated on a previous sentence for which parole had been revoked. The commencement date for the fixed term for the carjacking coincided with the expiration of that sentence. Accordingly, although the applicant was arrested on 14 September 2004, he did not start serving his sentences for these matters until 23 February 2005, almost 5½ months later.
29 It is well established that the fact that a sentence is to be accumulated on an existing sentence can amount to a special circumstance warranting a departure from the ratio otherwise required by the statute: see R v Close (1993) 65 A Crim R 55 at 60 per Hunt CJ at CL. That finding would have been open in this case but his Honour did not make it, nor did he record that factor as a reason for any decision: cf s 44(2).
30 The Crown also relied on the Judge's remarks at the conclusion of the sentence hearing where his Honour said:
"The intention is that he serve five and a half out of eight and a half. I think those figures work out to that don't they?"
31 Unfortunately, given that those periods in fact represent a departure from the required proportion between the non-parole period and the balance of term, that remark is entirely equivocal as to what his Honour intended.
32 In my view the appropriate starting point is the fact that the Judge expressly declined to make a decision that there were special circumstances for increasing the period under supervision. The obligation to record reasons for such a decision underscores its importance as a premise to the imposition of a longer period of supervision. His Honour was plainly aware of the terms of s 44(2). In the absence of a decision that there were special circumstances, the most likely explanation for the departure from the requirement of that section is that his Honour simply miscalculated the starting point as being 4½ out of 7½ where it should have been 4½ out of 6.
33 It is possible, conversely, that the miscalculation went the other way so that it is the non-parole period, and not the balance of term, that is wrong. However, it is difficult to reconcile that analysis with his Honour's earlier reference to the "simple mathematics" producing an increased period of supervision. If the starting point was the intended total sentence of 8½ years, those remarks make no sense. I am satisfied that the sentence entailed an error of calculation and that the error lay in overstating the balance of term.