Trade Agreements & Origin

USMCA RVC: net cost vs transaction value method for stamped parts: sanity check my math?

Stamped steel brackets, Monterrey plant. Transaction value method gives 58.9% RVC (needs 60%), net cost gives 63.4% (needs 50%). I believe we can simply elect net cost for these lines, but does the election lock us in for the full fiscal year across all identical goods? Certifying wrong here is expensive.