Yes. I think the use of powers in skill challenges is amply covered in the two DMGs.
But consider this:
Because of various mechanical considerations, including but not limited to the role of enhancement bonuses, the maths for combat and the maths for skills don't match up.
A related phenomenon occurs for NPC/creature skills, which are based on stat+training+half-level bonus, rather than the per-level basis for statting out defences; which means that most NPC/creature skill bonuses trail those of stronger-end PCs.