Shae,
Finally we meet outside the pub 😉
The problem is in the zone stamp. The one you are using is probably calling the ROOM_NET_AREA value rather than the ROOM_AREA value. The latter will display the actual area bounded by the zone polygon and will update instantly. The former is based on the wall thicknesses, etc and requires the Tools > Update Zones0/b] command. This command also will adjust zones to changes in the walls (you probably already knew this of course).
I recommend that you make or commission your own custom zone stamp. I haven't met two firms yet that that have the same requirements for their room names. Not much point in making do with something that doesn't work the way you want it to.