It gets extended 1 hr, if there are more bids it gets extended less. I may tweak the times but it is difficult in Hive to fully mimic Penny Auctions due to the small user base. This is an experiment and I will adjust depending on how it plays out. I also plan on running multiple auctions at once if it is popular enough. As well as far larger auctions for like 1,000 Hive and larger prizes.