[steelheadrob]

The way I look at it to add power on a supercharged car you can either add boost or add timing, but to do either you need the octane to support it among other things. In this case your tuner is reducing timing at the upper rpms at WOT because at the upper boost levels the octane gas you are running cannot support both the boost levels seen at upper rpms and the timing seen at lower rpms.