On the Toto's that use the unifit adapter, they come with the 12" one; a 10" or 14" version is an optional extra cost item. This adapter is installed on the flange, then the toilet is set on top of the adapter and anchored to the adapter. So, yes, any Toto that uses the unifit adapter (not all do), can substitute the 14" version for the 12" one that comes with it.