I just thought it is weird because it would seem that they would loose a lot of money off of doing this. Those few cents add up after a while. (for them and me)
They probably don't even worry about it because they make money hand over fist when they resell it.

When my yard runs out of change, they round up. Even on the scale, they round up.

The other day I brought in a pile of wire in a big plastic tub that probably weighed a couple of pounds. The guy told me to put the whole thing, plastic tub and all, on the scale. It teetered between 21 and 22 lbs. So he wrote it up for 22.