Hood and fender shake

I got 2 brand new BFG's for the back, had them mounted and balanced. Seems they had a bit of a time balancing them because I don't like to have the balance weights stuck to the outside of the rim so they do an alloy wheel balance and stick the weights on the inner edge of the rim and close to the hub center. Drove the car and it still shakes. Took it back and the balance was out again by 2.25 ozs. How can it change, the tire did not slip on the rim as we marked it and I didn't do any smokey burnouts. The rim looks to run true on the balancer, the hub center is true and the outer edges don't wobble or move up and down. I have some older chrome mod steel wheels that I guess I will have to try. This is beginning to really get to me!!! I have been to 2 different tire shops to have these wheels balanced so it isn't the calibration of 1 machine that is causing it. What next?