Give the Govenor a "Harumph!"apsuman said:I really hate having to say "Well the sage said X so that's official, I guess I was wrong." because it is so unsatisfying.
I will try to make this my last attempt to explain the feat (at least in this thread) and how it stack by MY interpretation of what the PHB says.
Since the various meta magic feats do not "see" each other when they are applied to a spell there can be no order of operation precedence. An empowered maximized fireball is the same as a maximized empowered fireball.
So you have a base spell, Burning Hands. You maximize it, this requires the caster to use a slot three levels higher. Everyone agrees up to this point.
Now you also want to heighten it. You heighten it by three levels. This has two effects, it raises the actual spell level by three spell levels at a cost of requiring a slot three levels higher.
So caster Ned is maximizeing and heightening and the result is that burning hands is now a fourth level spell in a seventh level slot because the three slot raises from the maximize and the three levels from the heighten combine.
That said, I think they could have done a better job wording the heighten feat.
Also, you are free to change it in your game. While I think it would be unbalancing it would be a rather small imbalance.
Mike