Government amounts are set out in the current USCIS fee schedule, Form G-1055, and are paid by the petitioning U.S. entity. Preparing the specialized-knowledge evidence is usually the larger internal cost, because it takes engineering time.
Engineering hours are the hidden line item
Hypothetical example: the company expects a filing cost and discovers that assembling the evidence requires the technical director to spend the better part of two weeks pulling procedures, writing explanations and reviewing project records. That time is real and should be scheduled rather than squeezed between projects. Budget for government amounts per the current G-1055 schedule, premium processing if the timeline requires it, immigration representation, and the internal engineering hours.
Add relocation for the household, certified translations of any French or other-language documents, and the cost of covering the specialist's Coalhurst workload while he is away. Decide in advance who pays for travel between the subsidiary and client sites, because that pattern of payment is also evidence about who directs the work.