The government charge is set by the USCIS fee schedule and is the predictable part. The unpredictable part is internal time: engineers and managers writing and redacting the evidence that proves the knowledge exists.
How to budget the internal work
Budget for people, not only invoices. Hypothetical example: a Lévis manufacturer of industrial ventilation systems transfers its configuration specialist and assumes the petition is a legal expense. In practice, the engineering manager spends two days assembling procedure documents, the HR lead spends a day on training records, and the specialist herself writes a technical narrative that counsel then edits.
That internal cost is real and should be scheduled so the people are available. On the external side, ask the adviser whether the quote covers reviewing the technical evidence, drafting the knowledge letter, handling a request for evidence and preparing the L-2 applications. Add premium processing only if the assignment date requires it.
Translation is usually modest, since most internal documents can be summarised rather than translated in full, but budget for certified translation of any document the officer must read verbatim.