Need a little guidance from the experts here. Swapping out a toilet, old one is removed, no leakage problems to speak of. PVC flange is in good condition but was installed at the tile level, not above. Is it adviseable to use a flange extension to bring it above the floor if the old toilet didn't have any issues? Old stool looks to be from the 80s, one going in is modern. Waste pipe is PVC.