Yeah, as long as you don't push the rocker paper across the ink/paper, it's fine. The blotter paper is so absorbent that the excess ink gets sucked right up rather than being pushed sideways.
As long as it rocks in place and doesnt slide. or if you have ink so wet it will kind of bubble up (Like thick dip pen ink, as FPs dont usually have this issue) they work great for getting a ready to go page without having to worry about closing a journal or folding up a letter to seal