I have ton of experience on wheel balancing... I actually do my own wheel mount and balancing. I find alot of time at general tire store is that they don't calibrate their tire balancer regularly... which goes off when they do volume work.

A few things you can look for yourself...

1. How much weight is installed on your wheel

2. What is the location of where they put it on... like hammer on weights on inside and outside... or stick on in the middle of tire only.

3. If you want to verify if your wheels are straight then jack up the car... put a stationary object near the tire and maybe a rod to get closer to the wheel and spin it... to see if the wheel goes in and out as in bent...

Another bent wheel is look at the wheel to see if you got 'flattened part of the wheel" where it is supposed to be round.