Immigration fees are the port-of-entry admission charge or, if the firm petitions, the USCIS Form I-129 fee from the fee schedule, plus the same admission handling for dependants. Corporate accounting, state licensing and travel are contract and professional costs, not immigration fees.
Keep three ledgers: government, professional, commercial
For a Canadian applying at the port of entry the government charges are limited to the admission processing fee and the I-94 record; if the engineering firm prefers to file Form I-129 with USCIS, the petition fee is set by the published fee schedule, Form G-1055, and premium processing is an optional additional charge. Those are the only amounts that go to the U.S. government for the immigration side. The state surveying licence, if the corridor requires one, is a professional cost with its own examination and renewal charges. Setting up cross-border invoicing, withholding tax questions and the corporation's own accounting are commercial matters the surveyor and his accountant decide. Mixing these ledgers leads to two errors: overstating what the immigration process costs and understating what running the engagement will cost. A consultation can confirm which fee applies, but it cannot substitute for the accountant on the tax side.
Hypothetical example: a surveying consultant receives a quote that combines border charges, a state licence application, vehicle insurance and bookkeeping for the Canadian corporation. Split it before deciding whether the assignment is worthwhile. The official government fee schedule or admission receipt settles the immigration amount; the state regulator settles the professional charge; the service contract decides who bears travel, insurance and tax-compliance expenses. Ask the U.S. firm to identify reimbursable project costs in writing, because an informal promise can disappear when invoices begin. The usual error is treating every cross-border expense as a TN fee and then assuming the immigration route is unaffordable. Build a dated budget with separate government, professional and commercial columns, and update it if the project shifts to another state.