Most of it goes into evidence assembly rather than drafting: retrieving records from accountants and registries, reconstructing ownership history, and organising proof of authority. Add a scoped legal review of the corporate relationship, which is often the decisive question in a family group.
Spend on the corporate question first
If the entities do not stand in a qualifying relationship, no amount of work on duties will help, so have that assessed before commissioning anything else. Ask for it as a separate piece of work with a written answer. Where the structure needs tidying for ordinary commercial reasons anyway, that cost belongs to the business rather than the immigration file.
Confirm official charges at the time of the relevant step. Hypothetical example: a family-owned commercial greenhouse operation spends several weeks assembling duty evidence before anyone examines the ownership chain, and the registry search then shows the two entities are held by different branches of the family with no qualifying relationship between them. A first review would have ordered that search in the first week and paused everything else until it returned.
Ask for the corporate question to be scoped and priced as a separate piece of work with a written answer, so the business can make a small decision before committing to a large one.