from what I can make out of German Tank kill figures there seems to be a bit of, shall we say, embelishment. I think the propaganda department wanted high figures to feed to the home front. There appears to be situations where any armoured fighting vehicle was classed as an enemy tank ( confusion of battle maybe ) a bit like the Americans who seemed to class every German tank as a Tiger when they met armour in battle. Also there could be quite legitimate reasons. In a big tank battle ( Kursk for example ) where there were many tanks lots of smoke, explosions, confusion etc. so who is to say that the same Russian tanks were not hit By 2 or more German tanks with all of them claiming a "Kill". There is no real way of counting unless you have won the battle decisively and can physically walk the battlefield and count. Tanks were also repaired after being classed as a kill so is that really a kill? Do you class self propelled guns as tanks or not? That is another factor. I doubt whether there is a complete and accurate figure of pure tank kills covering all the Waffen S.S. divisions for the war and, even if there were, how would you break it down to get a percentage? Life of the division, where it fought, these are all factors in such a question.
Well that's my view anyway, though there are probably more knowledgable people who can give more insight.