Define what the immigration evidence actually needs to explain. A process-knowledge account is different from a commercial legal review of every contract.
Keep the preparation proportionate to its purpose
Identify relevant examples, necessary explanations and any translations. Separate those costs and current official charges from unrelated contract advice; a larger legal bill does not itself establish L-1B knowledge. A handful of representative agreements explained clearly usually serves specialized-knowledge evidence better than a legal opinion covering every customer relationship on file.
Ask whether the underlying concern is proving how the applicant's knowledge gets applied to customer work, or something separate: where an applicant will spend most working time at a customer site, confirm who actually directs and supervises that work, since a placement principally controlled by an outside company raises a different eligibility question that no volume of contract review can resolve. Keep evidentiary document selection, translation and any customer-relationship legal advice in clearly separate categories so each expense can be judged against what it is actually meant to establish. Ask counsel to identify which agreements genuinely illustrate the applicant's specialized role before reviewing the rest, since a general legal opinion on unrelated commercial terms adds cost without adding relevant explanation.
Choose depth over breadth: a few agreements explained well typically outweigh a comprehensive review of terms that will not individually be cited in the filing.