Maybe I just never noticed how it worked (haven't played my reaver in a while) but did it always hit for 4 instant hits in a row? I don't macro or have a gaming KB or anything, this is just based on some quick tests. Impale was hitting for multiple hits consistently. The number of bleeds seemed to have no effect. I hit a norbog for 4 straight impales from one press of a button for a total of about 12k damage. I can't imagine this is WAI.