I think the OP is about indicating a swing, not about asking for help.
There is nothing in the manuals about this. If you think a point or announcing "swing" is good game management, fine; but expect the ding.
Yes, I realize that many coaches are not experienced enough to know that a swinging strike signal means a swing, so be it.
Also, I am not inclined to umpire for the sake of what coaches think or avoiding disagreements. One side will like, the other won't.
I'm surprised that a point was suggested at a NUS, wonder how long ago.