on my old toilet: you will be ok if the floor flange is higher if you
look at the toilet from under it and determine adequate clearance to
the floor flange.
and do not use a plastic funnel horn type of wax seal; just use a plain
wax one.
i goofed once and the toilet mysteriously rocked thereafter for a year
until i figured that out.
the flange must be secured to the floor. there are floor flange repair
kits and several options.
also see Wax-Free™ Bowl Gasket and other parts and help at:
www.fluidmaster.com

wrote:
I have a tile file on top of a cement floor sub floor. The closet
flange is about 1/4" off the floor. Does it need to be flushe with the
floor or will this cause problems? And should the flange be secured to
the flooring? If so, what type of screws should I use? I believe the
flange is a brass fitting to a lead pipe...