Under spell details, effect #3 it clearly says that this is considered a haste effect. Therefore it does affect dots. Also in Blizz's description of time warp they say:
[Time Warp] (level 85): Grants a passive Haste effect much like [Bloodlust] or [Heroism] to party or raid members. Time Warp will be exclusive with Bloodlust and Heroism, meaning you can’t benefit from both if you’ve got the Exhaustion debuff, though the movement-speed increase will still work even when under the effects of Exhaustion.
Which makes it pretty clear they view and treat it like a haste effect. Now if that bonus is enough to get you to that extra tick or not prob has a lot to do with how much haste you currently have.