Don't make me throw this thing!
I don't have MBT Nadir: I can't understand that rules reference and so don't get the point you're making.
Rule text from MBT (2016 ed. downloaded from GMT):
126.96.36.199 AP Hit Modifiers
If the firing vehicle’s turret was Damaged during a previous turn or previous action during the current turn, the modifier is –3."
Rule text from Panzer (2015 ed. downloaded from GMT):
188.8.131.52.2 AP Hit Modifiers
If the firing unit was Damaged during a previous turn or previous action during the current turn the modifier is –3."
The point is that the difference could come from one of two things:
1) Designer's intent with Panzer was that any damage (excluding a track hit) results in the Shooter Damaged -3 AP Hit Modifier, or
2) The rule wasn't updated in the re-release of Panzer and the Damaged Shooter -3 modifier should be restricted to vehicles with Turret Damage.
Only Jim can confirm one way or the other.