Please take note of the updated part of the auction rules. This is now listed under the "Both Parties" section of the rules :

To clarify ending times... if you say your auction ends at 11:00 PM, that means when the clock hits 11:00 PM, the auction is closed. Therefore, that means as a seller, you cannot accept bids that are timestamped 11:00. As a bidder, you must have your post timestamped before 11:00 to have your bid count.

If you have any questions, don't hesitate to ask. I tried to spell it out as clear as I could.