If anything I think you should be more lenient in the PA if you're going to take that into consideration - ie you want a clearer foul for a decision that big, not a more dubious one.
As for your description....I'd say it depends on the skill of the players for that one.
i've had 2 PA decisions that have stuck with me
1)Youth game (U/12-15 or some such), ball bouncing fairly slowly into an open goal. Defender running across the open goal, right on the line, to intercept. As he approaches, ball hits a divot and comes off at a surprise angle. Still towards goal, but back in the direction the player came from as he's still running. His arm is in natural stride and about it's furthest point from his body. Ball hits his hand, drops dead. I took the weakest possible option - PK (because I felt it was expected) and no card (because it was accidental - yes, I know!!). That's the first and last time I've justified a decision like that. Fact is, no foul occurred, I shouldn't have stopped play. It was completely unavoidable
2)Men's game, ball bouncing like a pinball around the PA. Attacker has arms down by his side, no idea where the ball is. I think it came from behind him at close range, hit his hand, dropped dead. He turned, kicked it into the goal. I allowed the goal, which was the correct decision.
I once had a local first grade coach yell at me to tell me there's no such thing as accidental handball in the box!! Hearing that makes me wonder what on earth he pays attention to - he's been in the game so long he would have seen hundreds of accidental handlings waved away!!