Yeah, also I have the same feeling, actually "the rules are pretty clear": "GEM and other sweetfx etc... are allowed" on POTW & GPOTW, instead, "GEM is forbidded on UESW section".
So, even though the matter may be more complex, as KAM2150 wisely pointed out, I will stick scrupulously to wording of the text, at least as I understood it.