Have experienced more than one point-of-impact change with Lead Sleds compared to other rests, especially with lighter-weight rifles--even sleds with no weight added. Usually it's not vast, but have seen it be enough that I prefer using a conventional rest.
When shooting really hard-kickers, I use a bag between my shoulder and the rifle, usually a 25-pound shot bag filled with lighter material like cat-box litter. It spreads the recoil over a wider area of the shoulder, without changing point of impact
Using a really heavy bag, such as an actual 25-pound bag of shot, can change POI considerably, though that depends om the shooter, position, and rifle/cartridge.
