On my earlier V7's I only put in the specified 170ml. Any more seeps out the level hole.
Usually, I change it every oil change, but have been known to skip it now and again, without untoward consequences, but I also mix in some 20ml of Nulon G70, a gear treatment, supposed to "harden" the bevels, or some such snake oil. Seems to work fine. Usually the old oil comes out "looking" good, so skipping a change now and again may well be OK. Only 220,000km on one of them, and 120,000km on the other, so early days yet.