It might have been 15 hours, but when you factor in 2.4 hour bidding window and any clock differences, it is very possible (and in fact happened) you would be within that 12 hour window.
I will place another vote in a bid window that isn't busy but this isn't something we did wrong. So I don't understand how user error would paint any bad picture on @buildawhale.
This is not something I can do again in the future.
RE: How to use @buildawhale to get a vote worth up to $3.41