Tool problem

I have recently purchased a 7 pin tubular lockpick. I have succesfully picked several tubular locks and have recieved training by a professional locksmith but i recently had a customer who had a kryptonite 7 pin standard size tubular pad lock and the circumference of my pick is very slightly to large and it seems to be pressing the pins down before my pins on the sides do which obvously destroys any possibility of opening the lock becuse i can not ajust the height of each pin individually. I eventually just cut the lock but i would like to know for future purposes how i can avoid this problem. If any one has any useful information please help me out here?