Some time back we discussed the potential of an offset bushing moving and if it was a risk.
I was doing an alignment on a customer car and could not get the correct amount of camber. Upon closer examination, one of the front upper offset bushing had rotated and snapped off the rivet that i used to hold it in place.
The issues were that the control arm i started with was a bit rusty from a part car, also the car took a decent hit in the front.
My point is that they can move and if your numbers are not adding up its worth to take a good look at that.