Yes.  Because post #283 initially had the end-time wrong.

After your last bid in post #282, Auction time should have been extended by 15-mins, to 4:38:00 PM UTC (and not until 4:33:00 PM UTC).

The subsequent bid by jackchan in post #284 at 4:33:02 PM was VALID according to the auction rules in OP.

Sorry for the confusion.