In Luscombe v Australasian Solicitors Pty Ltd trading as HHG Legal Group [2023] WASCA 141, a client retained lawyers for a family law matter.

The lawyers' costs agreement estimated $35,000-$95,000 if proceedings became prolonged.

A short while afterwards, the lawyers requested $50,000 from the client's daughter's estate for costs. The client argued the lawyers failed to provide a revised estimate as required when there was a substantial change to the previous disclosure.

The client argued the lawyers failed to comply with their obligation to provide a revised estimate when there was a substantial change to the previous costs disclosure. She submitted that when new issues emerged, including the request for $50,000 from her daughter's estate in July 2019, no revised estimates were provided as required under section 267 of the Legal Profession Act 2008 (WA).

The lawyers submitted in response that the client did not properly articulate what the 'substantial change' was to the previous disclosure. They argued that because the original disclosure estimated a range of $35,000 to $95,000, the request for $50,000 from the estate did not amount to a substantial change requiring further disclosure under section 267. The $50,000 fell within the range originally estimated.

Key legal principles from Luscombe on revising cost estimates:

There was an implicit finding by the first instance Judge that by the date the $50,000 was requested, there had been a substantial change requiring a revised estimate under s267 Legal Profession Act 2008 (WA) (Mullins JA at [80]).
The lawyers' request for payment for trust money from an external party did not constitute proper written disclosure of the substantial change as required by s267 (Mullins JA at [81]).
Litigation lawyers should be capable of providing estimates of costs in difficult litigation along with variables affecting estimates (Vaughan JA at [7]).
Uncertainties in predicting required work can be reflected by appropriate qualifications of estimates (Vaughan JA at [7]).
What is required are estimates, not guaranteed predictions (Vaughan JA at [7]).
Lawyers should explain variables potentially affecting estimates and qualify estimates for uncertainties (Vaughan JA at [7]).
Estimates can be qualified where precise estimates are difficult due to imponderables (Vaughan JA at [7]).
Focus should be practical estimates based on experience, not guaranteed predictions (Vaughan JA at [7]).