Originally Posted by
msrinivas
I am sorry if this was mentioned earlier in the post, a weird one as mentioned above, but as a PLAT you need to use your 500-mile stickers for upgrade. They accrue by how much you fly. So if you don't fly much then you have less stickers to upgrade. Of course you can shell out $'s and buy them too.
Good point to mention. As an alternative -given what we assume to the OPs high mileage balance, s/he could also redeem miles for upgrades.