What you're overlooking is this:
The FINRA short sales for the day MAY include borrows, and they may not. Those FINRA shorts also include both shares sold on the ask which are immediately covered with a buy on the bid (the mm shorts the ask and covers on the bid to pocket the difference), and new shares entering the market, which the mm usually sells short on the ask when possible to avoid tanking the sp and then covers with the t trade (drawn from the block of new shares he has) at a price that usually reflects the volume weighted average price he was able to sell at less commission.
Now, I have seen t trades that were more a case of moving large blocks from one account to another, but it was not a stock trading at a penny in need of cash...