Increases item stack / payload size for most vanilla and modded items by a customizable multiplier (Default: 10x)
I've just installed this mod and plastic, iron, copper and all the other item stack size muliply by 10, but not the coal. it remains at 500 it is the standard stack size 50 (I have used stack sizing mod for a long time I don't remember)?
As per the Factorio Wiki, The default coal stack size is 50 so 500 would be correct with a 10x multiplier.
https://wiki.factorio.com/Coal
Ah. Sorry for that. :D