I cant see your entire capx so I am not sure, but this is a suggestion on something you can check.
From the tiny bit you of actions you have shown there is nothing stopping it from going into that condition many times. It depends on if the position you are setting is a whole different location, then my comment is invalid. But if the location you are setting is still below the distance of the 16 then you will keep on deduction 1 from pieces.
If the above is a correct assumption you need to add another condition, could be a check for if dragDrop is disabled, or your could set a variable on the p92 object that it has the right position.
From what you have shown me that is my best bet. If that does not help, I would need some more info to be able to help you.
Hope it helps.