calls at 3B by PU

[Tap]

We've got adult SP, with runners on 1st and 2nd, no outs. BU is inside the diamond, between 2B and pitcher [USSSA mechanics].

Batter hits routine ground ball right at SS who (despite having a 4-run lead in the top of the 7th) does not make the easy play at 2nd, but instead throws to third. I'm PU. Our association, which does USSSA and ASA games, has the PU take plays at 3B in this situation, like the ASA manual says [the USSSA rule book states that BU take first decisions or plays on all bases, but we don't follow that].

I start toward 3B, perhaps a touch late (but I had to make sure to avoid the batter and then stop running to make the call), and the throw goes to F-5, who gets his feet tangled up near the base, probably missed touching the base (may have touched it), but appeared to touch the runner on the chest before he got to 3B, so I call him out, though I may have kicked the call since I didn't have a great angle and the fielder may have missed him.

The hitting team, in the 3B dugout, complains vigorously, but never asks me to get help from my partner, who was probably looking for a play at 2nd anyway. Thus, I don't ask for help and we play on. I'm not sure whether the other umpire had a decent view of it, and asking for help without being prompted may have shown that I was unsure of my call, but should I have asked him for help? The BU is an excellent umpire who may have had a better view. Any thoughts?