I suspect that a lot of AFVs in Twilight will have patches indicating major hits on their armour in prior engagements.
*Can* you 'patch' MBT Armour? Or patch it in a meaningful way rather than, say, just slapping some tread links over it or welding some mild steel plate from somewhere? Neither of which would be particularly helpful against AP/HEAT type weapons. Heck, maybe not even against heavy calibre smallarms.
And then there's the likelihood that any penetrating hit against MBTs will burn the damn thing up, maybe set off the internal ammo, and do a number on it.
I know the Israelis used a lot of captured Russian MBTs but I've seen pictures of a lot of burnt out hulks still on the old battlefields, so how many of the ones they refurbished were burnt out hulks?
I suppose if the HEAT or AP round hit the engine compartment it might be possible that the whole tank wouldn't be destroyed and the engine might be replaceable from a mobility killed model ...
But I suspect a very large nonzero percentage of KOed MBTs will *remain* KO'ed.