Piling planks by 3 peices each, you get to 18.
Cannot add 3 planks to 18 planks, they switch.
When dragging planks to my inventory, they split and go in by piles of 10.
You cannot pile up whatever got split and inside the inventory, only dropping them on the floor and piling them up again up to 18 or 20 if you are lucky.
When dragging a pile of planks larger than 10 to the car, it splits and takes only piles of 10.