Mostly into evidence assembly and legal analysis rather than filing mechanics. Someone has to gather years of scattered business records, and counsel has to weigh a fact-dependent claim. Ask whether the quote covers that gathering, the drafting, dependent work and later evidence requests separately.
Ask what a weak finding costs
Before committing, agree what happens if the review concludes the function claim is thin: whether the scope includes advice on alternatives, and whether fees already spent carry over. Decide internally how much staff time you will spend retrieving old documents, since that is a real cost the invoice will not show. Confirm official charges at the time of the relevant step rather than relying on any figure quoted in advance.
Separate the cost of proving the function from the cost of building it. Where the function claim is currently thin, part of the work is organisational rather than legal: assigning a budget line, recording a decision right, formalising an authority exercised informally for years. That work carries value for the business whatever the immigration outcome, so it is worth funding on that basis rather than charging the whole of it to the case.
Ask the adviser to mark which recommendations are of that kind and which exist only for the file. Hypothetical example: a marine survey firm writes down its equipment replacement authority for the first time, which improves the record and also settles an internal argument that had been running for two years.