Russia has no trouble keeping up in tech while they're Eastern (in fact you need to go out of your way to get far enough behind to westernize), but that isn't the point. The point is improved units.I don't have the link to the math, but someone calculated that any later than 1700, westernizing for eastern tech groups is more expensive in admin points than just sticking it out.
Granted it may or may not be worth the trouble, but that does not depend on how many monarch points it saves.