I know it's really pedantic but when i cut floorboards i like to do it dead centre of the joist so the load is as perfectly distributed as it can be. I don't have the metal plunge cutter but the nails that are sometimes in the centre line are annoying the hell out of me, just to be sure, it wouldn't do the metal plunge cutter any harm if it hit a bit of wood while slicing that nail in two?