Only problem I ever had was with the dispenser, seized up (if it ever does that, it's a super easy fix BTW).
Never had it go out of whack, EVER, and I don't use a line conditioner and I use it in a cold garage without warming up and it works fine. Every time. I check it randomly using a triple beam. The check weights are also spot on. Never been dropped, but it's seen some abuse I guess. Been knocked around and taken apart for sure.
Have you weighed your check weights? Are they off? .2 isn't much but it is when you are using one of these devices. If the .2 is consistent, why not just program it out?
Or do you mean it's calibrating fine but then throwing .2 over often? If that's the case, a mcdonalds straw will usually do the trick (this is a common DIY for using flake powders in those units). They commonly overthrow some powders.
Also, the dispenser drive can crap out and it won't trickle right anymore. My motor sounded sluggish too, I took it apart, fixed it (easy, like I said). Hope one of these helps you.
If it's all over the place, I'd send it back if you can.