It affects the outcome more than the cost. Payment and supervision terms are read as evidence of whether the placement is a controlled service or labour for hire, so drafting matters commercially and legally.
The clause is cheaper before signature
Hypothetical example: Filing fees are published in the USCIS fee schedule and are the smaller consideration. The expensive scenario is a signed client agreement whose terms describe the technician as effectively working for the client, discovered only when the petition is being prepared. Renegotiating a contract to support an immigration position is difficult and sometimes impossible, whereas including the right terms during drafting costs nothing beyond attention.
A Cavan Monaghan firm negotiating maintenance-station work should therefore involve the transfer question at the point the scope of work is written: define the deliverable the client is buying, retain supervision and responsibility within the petitioner, and avoid language that hands day-to-day direction to the client. The commercial terms and the evidentiary position are the same document, and it is worth drafting once with both in view.