I'd recommend some movement for sure. When my refugium gets slow, due to overgrowth of macro, I get some algae sheets that aren't there when the movement is better. Also, for the intent of filtration and dispersal of microplanktors (the heart of the refugium philosophy) I like movement to provide the in/out workings of the water through the macro fields.
*** Oh I just re read the post. You were asking about additional movement, other than what your in/out plumbing allows...I'd take a look at the little stringy stolons on the macroalgae. If they are waiving back and forth, that's usually decent movement without any extra. If there are dead spots in many areas or in places where the macro clumps make a lot of coverage, I can see adding a little powerhead to keep it flowing.