Most of the real cost sits in the business rather than the file: hiring or promoting successors, overlapping salaries during a handover, and the delivery capacity lost while you train them. Legal and document work is separate. Ask for an itemized scope before assuming the file is the main expense.
Budget the handover, then the case
Decide how long you can carry a successor alongside your own delivery work, since that overlap is what makes the managerial description true. Then ask counsel to scope the assessment, the support letter, dependent work and responses to later questions separately, and to say what happens if the review finds the balance still wrong. Confirm official charges at the time of each step rather than budgeting from figures quoted months earlier.
It is worth pricing one further scenario explicitly: the review concludes the proposed role is still primarily operational. Ask what that outcome costs, whether it means a postponed filing, a different classification, or a longer handover period, and agree in advance who carries the additional work. Building that branch into the engagement removes any incentive to describe a role optimistically in order to protect a budget.
Hypothetical example: the owner of a meat-processing group budgets a successor's salary for four months, learns that a realistic handover runs closer to nine, and reprices the transfer itself rather than trying to compress the evidence.