Government charges appear in the USCIS fee schedule, Form G-1055, and do not change when a request for evidence arrives. The cost that does change is professional and internal time, because a specialized knowledge response has to assemble material the original filing should have contained.
The expensive part is the second assembly
Requests for evidence are common in this category, and companies that treat them as a formality respond badly. A serious response often runs to a hundred pages of exhibits: the protocols, the filings, the design records, a revised support letter, sometimes a declaration from the affiliate's research director. Gathering that under a response deadline costs more than gathering it calmly at the outset, and it pulls the same senior people the project needs.
Premium processing, purchased under the schedule, accelerates the decision but does nothing to make the evidence better and is wasted on a thin filing. Two indirect costs deserve a line in the budget. A delayed start can push a trial programme past a planting window, which in seed work means a full year.
And a denial recorded against the company becomes context for its next petition, so the first filing is worth over-documenting.