IMO, a deer can't fall a foot in 1/16 of a second. Adeer's first move is straight down, to cock those mighty legs, to bound away. Since gravity is just so strong on a 150 lb. deer, then I don't think that bulk is capable of decending the required 12 inches to duck the approching arrow. But what do I know, I went to school with Jethro and he was smarter than me!
BBO