I'm seeing +65 reputation in my reputation tab (on July 8 / 2 days ago), but I'm getting only 12 up-votes for that post. I'm confused about why that happened.
One of the upvotes on your question was reversed with the serial voting. Thus, you'd only have 12 votes left on your question. Your history would still show 13 votes that gained you reputation, because the -5 from the reversal would be included in the -300.