vibration problem on f10 models

hi all im new to this so go easy on me i work as a contractor for bmw i fit tires change wheels etc,im trying to work out why the f10 model is such a nitemare to stop vibration in the car at certain speeds. i fitted 4 tires on model balanced wheels spot on 3 weeks later it was back with vibration probs balanced wheels again they were out by a long way corrected them again but still no good ahh. ive had to balance 8 wheels today one car had done 1430 miles with vibration probs and i have to do another one to morra.... looking at the wheels ive balanced or from factory i need to move weights round wheel most of the time as if weights in wrong place(or the tires are moving on rims due 2 braking and pulling away) and also there seems to be a lot of weights on the wheels as per a car without runflats ... but why the f10 some fing is not write with these wheels or a massive batch of tires xxxx