I believe that the rule is, (but google that just to be sure) that 75% of any single component must be "Made" in USA for it to count toward the percentage of product parts which accumulatively make up the vehicle's domestic content. So, yes there's some fuzzy math involved in it.
Strangely, we are led to believe that this is necessary because of greedy union labor benefit's. And while I don't wish to start another union type thread, if we were to compare the wages and benefit packages of foreign manufacturer's building vehicles domestically the parity would be obvious. But we wouldn't want to have facts get in the way of promoting a globallist agenda. I'm happily surprised that nobody has yet made an anti-American worker statement to blame instead of looking to the real problem. Companies like Honda, and stinking Toyota, have a very efficient, focused and goal oriented management team. Companies like GM had reports printed for years about their overburdensome bureaucracies of multiple management teams of which none were working together. Ford sadly has many, but not As many vestiges of that business model which is an utter failure.
But I believe too that those who truly make the decisions up there in Dearbornistan are scary intellegent and operating with intellegence data that we as the general public aren't privy to or even aware of.
Of course, if we could rein in the bureaucratic power of the EPA to make the US uncompetitive in manufacturing while simultaneously forcing importation duties on foreign made goods and materials coming from countries which do not have our environmental or worker protection policies on a yearly snapshot basis, then I truly believe that we could not only be competitive, but maintain a standard of living and force the rest of the world to implement policies of their own that'd make their localised environment and worker's safer, healthier and better compensated without enduring this current 'race to the bottom' mentality of the psychotic's who are running the global show now.