Please follow correct BIN procedure to offer and accept a BIN price
6.2.3. An auction cannot be modified once a bid is placed with the exceptions of its Buy-It-Now ("BIN") price, bid increments, adding payment methods, and/or adding additional domains at no extra cost. Once a bid is placed, every allowable change (the exceptions just mentioned) must be posted to the thread as a new reply as well as updated in the original post before it becomes effective and valid (e.g., a BIN price cannot be accepted until this is done). BIN prices are not reserve prices and therefore do not affect rule 6.2.10.
6.2.4. A Buy-It-Now ("BIN") price may be changed (added, reduced, increased, or removed) on an auction prior to it being accepted, in accordance with rule 6.2.3. The BIN price in an auction must be publicly accepted by a buyer.