The port-of-entry application carries only the small TN and I-94 fees on the USCIS schedule. The petition adds the Form I-129 filing fee, any asylum-program fee and optional premium processing, all listed on Form G-1055, plus the professional time to prepare the exhibits.
The petition buys certainty; the border buys speed
At the border the applicant pays the TN application fee and the I-94 issuance fee, both modest amounts set out on the USCIS fee schedule, and nothing else beyond travel. The petition route has the employer file Form I-129 with its base fee and, unless the employer is exempt, an asylum-program fee, and most employers add premium processing to obtain action within the service window. Read the current figures from Form G-1055 rather than from an older quote, since they change.
The larger cost of the petition route is preparation: assembling the support letter, degree evaluation, organizational documents and any explanation of a staffing structure takes professional hours that the border route mostly avoids. What the petition buys is a written decision before the engineer resigns or relocates, which for a two-year contract with a family move is often worth the outlay. Credential evaluations for foreign degrees and translations of French-language transcripts are charged by their providers regardless of the route chosen.