Players shouldn't be allowed to jump more than one tier at a time. Once you change tiers, you should have to re-establish your scoring average within that tier. A 10-20 round minimum completed rounds before advancing again.
The hack tier low end is 134.77? You should drop that a lot. A player who shoots a 98, followed by a 104 is already on the cusp of being promoted. That doesn't make any sense. You'll never have any competition in this tier if folks can bust out of it with 2 very mediocre rounds.