Additional damage only would most likely occur if you were shooting 2 blade broadheads, think about it, with more than 2 blades, any way the head is being pushed you are pushing against tissue with the flat of a blade. However, as everyone said, with one hole blood is generally very scarce. Also, the deer is feeling the arrow more if it is inside, so I think that it would run faster, ie further(I have noticed this on non pass thoughs, anyone else seen this too?)....so in the end you have less blood for a longer distance.... I will go for a pass through.