[18] Sections 48(2) and (3) of the Act refer to "fees and costs". In s 3 of the Act "costs" are defined to include disbursements and "fees" are defined for work of a practitioner or firm as meaning charges, other than costs. Fees are therefore in the nature of professional fees and costs are therefore in the nature of disbursements. Section 48(3) of the Act requires that when the client agreement specifies the fees and costs payable by the client for the work, it must specify a lump sum amount or the basis on which fees and costs will be calculated (whether or not including a lump sum amount). Clauses 4 and 5 of the terms of the agreement deal with calculation of the plaintiff's solicitors' fees and costs, additional to the professional fees, respectively. This is supplemented and given precision by the letter dated 22 November 1999. That letter stated that the plaintiff's solicitors' fees would be determined "on a time costed basis" in accordance with the client fee agreement dated 25 August 1998 and identified each partner, associate and solicitor who would be performing work in respect of the matter and his or her respective charge out rate. A range of charge out rates for an unnamed clerk is also specified of $110-$125 which, in the light of cl 4.3 of the terms of the agreement, would be read as an hourly rate. It is not fatal that a range is given of charge out rates for a clerk, when the bulk of the work will be undertaken by solicitors for whom precise charge out rates have been specified. The letter dated 22 November 1999 gives as an estimate of fees and costs the sum of $1,000 to default judgment and $3,500 - $5,000 to summary judgment, depending on what defences were raised. The plaintiff's solicitors have therefore provided the basis on which fees and costs will be calculated, ie on an hourly charge out rate with most of the rates specified precisely, for professional fees to be determined on a time costed basis and costs in the nature of disbursements to be determined by those actually incurred. An estimate is given of both fees and costs to certain stages of the work. It is submitted on behalf of the third defendant that the terms of the agreement together with the letter dated 22 November 1999 do not enable the plaintiff to calculate with any precision the basis upon which it will be charged fees and costs. What s 48(3)(b) of the Act requires is a specification of the basis on which fees and costs will be calculated. It does not require that those fees and costs can be calculated with precision, prior to the work being undertaken.