it's only an approximate wait time, and if there are a lot of people in the queue (which there are right now because the first set of strains finished up today), it can be significantly longer.
well then a lot of people must have signed up in those 20 minutes, because the queue is processed by the time you signed up. it can happen. you shouldn't have too much longer to wait, though, based on the number of people ahead of you now. :)