Some examples I came up with:

Injection Molds, 8480.71.8045, they are from Japan with Japanese steel over 15%. They will get 11.9% added to their column 1 rate of 3.1% to bring it to a flat 15% duty under 9903.82.10.

Other parts ,8479.89.9599, made of 22% US smelt/cast aluminum. They will get 7.5% added to their column 1 rate of 2.5% to bring it to a flat 10% under 9903.82.07.

Other car parts, 8708.99.8180 with more than 15% steel content and steel melt/poured in US, gets 9903.82.06 and has a flat 10% added to the normal duty rate.