the high school exit exam

here in california (although i'm sure we're being watched and probably emulated soon), there is much debate over whether the high school exit exam is fair, is accurate enough, is administered properly, etc....the list goes on. but one problem: it only tests up until the 10th grade level of school at most to begin with. i'm sorry, but if you're in 12th grade, then that means you're presumed to have passed the 10th grade. you might think you forgot, but the human brain is capable of things that will startle most brain users. so if you cannot pass a test on the 10th grade material after six tries, then maybe you shouldn't be in the 12th grade now at all. (before you get your panties all in a bunch, special ed isn't being factored into this equation. i'm quite aware of the fact that not everyone is cut from the same cookie cutter.)
but on a slightly different vein of thought, if we are only going to test to the 10th grade level, why not just test them at the end of 10th grade for everyone? if you pass, then congratulations, here's your diploma, now go out there and be somebody. if you don't, then you have five more tries and up to two years of school to try and get it right. we could potentially save billions of dollars from being wasted on kids who don't need it (aka those who pass after 10th grade). the saved money could be shifted to better educate kids in the lower grades to increase the passage rate as well as increase funds for community colleges and universities. (or at the very least balance the state budget.)
how this would affect the dropout rate might not be crystal clear and would probably take awhile to fully be actualized. but i doubt it would be any worse than the current stats for dropouts, which are pretty disheartening. if california (and the rest of the us as well) is to compete in a 21st century global economy in the mid-long term, something must be done soon to combat the drastic cuts to education both in primary, secondary, and higher education levels.