Momentum support and chaos DoT skills

Momentum does not increase damage over time for Essence Drain skill.
Tested by casting Essence Drain and not moving at all, then casting and moving constantly - final damage is identical in both cases.
Maybe Momentum is not supposed to support DoT skills, with wording "while using the skill" meaning channeling?
Momentum cannot support Contagion for some reason.
So there's an idea for you to think about if Momentum should be able to support DoT skills or not. And also what it means to be "using the skill".
I think it should support, because there doesn't seem to be enough damage scaling for chaos DoT skills.