So you’re saying that even with only 2 balls remaining in Toys MB, that you can do one Lock/PFx sequence to get 2x, and then with your remaining ball (assuming physical locks are enabled) you can do the sequence again to get 3xPF, but then have both balls in play? This is identical to Groot MB behavior, so it wouldn’t surprise me if this is how Toys behaves.
But I seem to recall from gameplay that once you’re down to 2 balls, the game won’t let you qualify 3xPF.