I know pitch will definatly change POI. My gun shot low and when I increased the pitch I was able to bring the POI up 4 inches. Do you still have the pattern stock, if so reinstall it and see how it shoots. Somthing sounds very wrong if you see a lot of rib and it shoots low but when you site it like a rifle it hits dead on. If thats the case you should be hitting very high. This is a very interesting and I can see frustraiting problem. I would definatly try and reinstall the pattern stock to see what happens.
