I will try and answer a couple of your questions so here goes. I shoot on the ground and off the top of a barn for pratice and I never see a noticable differance. Now mind you I never shoot straight down either. But in my uneducated days I shot a nice eight pointer that was only about five yards from base of tree, say ten to fifteen feet. The arrow went right were I aimed but did not understand the lung set up to do it right. Anyway, I only hit one lung but did not know it at the time. But when I got out of stand my arrow was covered in blood and had asmall trail for about ten feet and then nothing, not even a drop. But I did know enough not to push deer when shot so I left and came back next morning. The biggest mistake I think in not finding deer is that they were pushed when shot. Usally the hunter will go to there edges of property and stop there. Then the deer runs past that edge and dies just outside of the hunters area. When deer are hit they only run far if pushed. If not pushed they will only run fifty to say one hundred yards or so and then stop and die. But back to story, I came back next morning and deer was about seventy or so yards from stand and hardly any blood on ground by him, not pushed and laid down for his final dirt nap! As Squirrel said I have found the best method for finding deer is the grid search, one guy can do it, just takes longer, have found alot of deer with the grid. Also if you had good solid blood on arrow it was fatal! only wet heavy blood can come from lungs or main vains. As with my deer I hit high and only one lung. I think cause it was high the blood never ran out and just filled the cavity. One thing I have always noticed with my deer is that if the shot is in the lower half of the lungs I always find alot of blood. But if I hit high the blood gets less and less. I would say your friend got a one lung shot, pushed the deer away, and the deer bled out inside. If he hit muscle the arrow would have the red/clear smeared look. And gut shots, well you can get all kinds of stuff on that one. Also the bow is not at fault it him!