Alot of brands suffer from this, stuck sidewalls that don't fully seat.
My guess is that you are taking your wheels/tires to ignorant people who don't work with low profile tires too much.
The simplest way to get this solved is to apply bead sealer on the lip of the tire (not the glue kind but the "grease" kind) This will make the tire slippery at the lip and it will seat. Just make sure you never put more than 50PSI on the tires just to seat them, the risk of a belt being moved out of place could cause premature tire wear, as well as bubbles on the sidewall and bumpy, uneven wear.
