If it doesn’t overshoot it’s fine. Modern low self discharge (lsd) nimh’s like eneloops do not like to be held on indefinite trickle charge or be overshot. Older nimh were less picky about overcharge so long as current was below its reabsorption rate.

But really thinking about it, this method doesn’t match up with how I’ve experienced nimh behaving on a charge. Intuitively, I want to say this will cause some (reversible) loss of capacity due to not fully charging the cells. It probably works best on new-ish high quality cells, ones with a few full cycles on a good charger. negative delta charge detection won’t work here.