I should point that all votes from banned members do NOT persist. The total votes by your name isn't updated when I run my script.
However all the votes themselves are removed. So the calculation used by the forum software to protect you from downvotes -- the 12% figure -- comes from your ACTUAL votes, not phantom votes that no longer exist. I think that's the important part.
Because the more downvotes you get, the more downvotes you CAN get, if you know what I mean.
Long story short, a given member can only be 12% of another member's downvotes. If you attempt to be slightly more than 12%, the system prevents you from making the downvote. It's to protect against enemies and malicious voting.