I think the DMG/Delay ratio is too low to be a difficult Tmap drop, and I would like to suggest either switching the item to a VE Tmap drop, or tweak the DMG/Delay a bit.
Agreeing that the bow is dumpy. Ashenstrike is basically the measuring stick for bows, and a difficult tmap drop should be able to beat ashenstrike in its sleep.
"and I would like to suggest either switching the item to a VE Tmap drop"
there's already a 20-24 or 20-30 bow in the ve or e map, best option would be to tweak it (i'll post the bow (the one from ve/e) stat/img when i get home since i don't recall name by mind) ... or if some1 could post it for me