Tire size differences will vary according to the bike too. My Cannondale SSix EVO rode very rigid with 23's and I hated the ride. Then, I put 25's on it and the ride was much more compliant to my liking.
I put the same 25's on another bike (from 28's) and couldn't tell the difference.
I think before I would make such a minute tire size change, I would play around with air pressure first.
Bikes, tires and people are all different and with some many variables to allow for, the assumed results may not be worth the expense or effort.