snip
Well that explains it. I might be getting small discrepancies but this pushes the difference between that 4.5%/13.5% to 8.27%15.53% if we were to account for the reload bonus which is close to what the DPS comparison showed up in the patch notes.
So no, the cooldown modifier doesn't increase the dmg at all ranges between 15/20%. It's closer to 5% to 15%.