The main variable is evidence preparation. Assembling proprietary documentation, obtaining internal approval to disclose it and drafting a technically accurate description takes engineering time as well as legal time. Government fees should be taken from the current USCIS fee schedule rather than from an older quote.
Count the engineering hours, not only the legal ones
A specialized-knowledge case is written jointly by a lawyer and by somebody who understands the technology, because the lawyer cannot invent the technical description and the engineer cannot frame the legal test. Budget for both. Expect internal time to locate documentation, to redact anything commercially sensitive and to obtain sign-off on what may be filed. Where an employer resists that time commitment, the honest response is that a thin evidentiary record can make these cases difficult, and the effort saved at drafting may reappear later if more evidence is requested. Ask for a scope that identifies who is doing which part, so the engineering contribution is planned rather than requested at the last minute.
Hypothetical example: Minh, a flight-simulator calibration analyst, is quoted for a filing before the client-site contract is reviewed. The record must show qualifying foreign employment and genuinely specialized knowledge tied to the proposed role; L-1B classification has a five-year maximum period. Separate government charges, document retrieval, translation, business restructuring, and professional review. A quote is useful only when it says which facts it assumes and what additional work could change the price. Ask what happens if the facts require a different filing channel or a revised business arrangement; that question prevents an early estimate from being mistaken for a fixed total.