More of a general question than anything. Does anyone know why toilet manufacturers don't make the lip on the toilet flange long enough to extend down into the floor drain flange, thus eliminating the leak problem? I know that the wax ring still would be needed for sewer gases, but, wouldn't an extended lip prevent water leaks without the need of a wax ring? They do make wax rings with a rubber flange for the same purpose, so, why not permanently part of the toilet?