I tested this by taking both the ebony and dragonbone bow's out a field and I aimed at a tree a long ways off - I used ebony arrows for the ebony bow and I used glass arrows for the dragonbone bow - after shooting both and running out to inspect my shots the ebony arrow appeared right where I aimed/expected to find it, the glass arrow was much lower but in line with the ebony arrow so I'm sure my aim was true for both. Not satisfied with this I repeated the test 3 more times, even switching up which arrows I fired from each bow and every time the dragonbone bow shot low at long range... how disappointing. I did not move my character between shots or move the point of aim when switching between bows either.
Not a fan of the dragonbone arrows though, they should have made them serrated tri-bladed points, not the forks that they appear as, they don't even look like they should fly very far and the daedric arrows already covered that prongy look in a way. Shame. That's my opinion though, I'm sure some people out there like them just fine.