I always WANT to have two holes. Does it always happen, nope. Anyone who has spent anytime in the woods hunting will tell you things do go wrong. There is not always that 100% perfect shot, and therefore not always those 100% perfect hits, blood trails, recoverys, etc...
I have shot deer high, as in an extreme angle from a stand, and if there isn't an exit hole, there will not be much blood at all pumping up and out of that high entry hole.
I am anxious to see some photos/video of many of the new heads this year, including the Blood Runner.
Mark