We tried that in the beginning when we started these Challenges. That became a very difficult task. Believe it or not, there is a lot of time spent handling these Challenges now and adding that would be even more time that we just can not commit. And there is also problems with this particular idea:
The High prices and Low prices are within the window of trading so what this does is it creates a loophole that some participants can expoit. When the price of one of these coins just drops continuously, all they have to do is mark down their Price Pick as the Highest price within that window and they are perfect with their selection. This makes it unfair for all the other participants.