I "think" it was confirmed last night here, that shorts can "borrow" shares, and then can wait, aka, they then have the option to go short/sell or they can merely return the shares they borrowed. No effect upon share price. So as the number of shares "borrowed" goes up and down, it does not mean short are covering. They "borrowed" share were never used to short the stock. They do however, have to pay interest on the borrowed shares.

I've never heard details on the interest shorts pay to borrow shares. If they interest rate is 5% or 10%, either way, that is very low if they only borrow shares for say 5 days, if that is an annual interest rate. 10% per year for only 5 days, would be 10% divided by 365 to get daily interest rate, then times 5 to get interest rate for 5 days, very small.