i disagree. even a few mm in one place can put things out alot more somewhere els.
i was messing around with my camber on the front a few weeks ago and it only took a couple of mm movement on the bolts to move the tyre quite alot in or out of the arch by cm,s.
so maybe that could be doing the same kind of thing.
You can disagree all you like...but a Mk3 balljoint has NO caster adjustment on it...it has fitting tolerances that are 1-2mm, the difference of which falls within the acceptable castor tolerance on the alignment.
Mk3s use the two strut bolts as camber adjustment..what you can get on the balljoint doesn't even come close to what you can get on the strut.
you can get maybe 6 or 7 degrees of cambwer adjustment on the front.
There is NO castor adjustment...for it to be out of tolerance wildly something has to be bent.
Even if you add up movement on the subframe bolts and movement on the balljoints, you are looking at fractions of a degree - 0.2-0.4 degrees...which I doubt is enough to fix this problem.
On the Mk4/TT/S3 (that had NO camber adjustment) moving the balljoint 10mm gave approx 0.2-0.3 of a degree of additional negative camber...
so what will 1-2mm give?
But, as you say, a few mms here and there has the affect of throwing the lot out...