The way to assess the actual placement of the flange to determine the rough-in dimensions is to measure from the bolts that hold the toilet to the flange straight back to the finished wall.
You usually can't move a toilet much more than maybe 1/4-1/2" from its optimum position, if that. Otherwise, either you won't be able to get the bolts through the toilet, or the seal will leak.
Some of the Toto's use the same toilet, and use a mounting adapter to let it work at either 10, 12, or 14". These adapters are specific to the toilets designed for them, and can't be used generically on others. I've got a Vespin and a Carlyle in my house, and both of these (along with some othermodels) use the Unifit adapter, so can be used at 14". The Toto Aquia uses a different adapter, and not sure if it is available in various rough-ins. Some of the toilets are built for the non-standard 12" rough-in, but your choices are smaller and the price is often greater since there isn't as much demand.