I'm not sure that taking 16 AP classes is the same thing as taking 16 AP tests. All four years of my high school English classes were called AP English, but there was only one test. I would have had the same approach for math if I hadn't dropped Calculus senior year... I'd have only taken the one AP test for Calc, though I'd have had three straight years of AP math classes (9th grade Geometry was called Honors). That's 7 of your 16 right there. For school districts that split Calc into 2 classes, you could get half the requirement in only two subjects you were going to be taking anyway.

The next tier down was called College Prep in my school district. The CP kids did waaaaaayyyy more hours of homework than I did.