That's the anecdotal number, there's a few spots of obstruction. A/G has the
best list of norms that I've seen. The more spots you obstruct, the higher the AHI. Degree of obstruction isn't significant to the AHI but it could mean the difference between UARS, hypopneas, and apneas.
Also, everyone's airway is different. The big factor is how much soft tissue do you have that the skeleton is intended to hold up. You can kind of approximate it by looking at the tissue on the outside. Is the skin under the mandible well supported, tight like you see on models? Or is it kind of double-triple chinny? My airway is 9mm at its narrowest and I have a high AHI. By contrast, I know of 3mm cases that have no OSA (but it's very rare). The other thin to remember is that weight gain and age (through sagging) shrink your airway over time. Some even think that everyone develops OSA at some age and the high normal AHI labs look for is an indication of that. A smaller airway simply means that you get it sooner than others would. Unfortunately, there appears to be no studies done on predicting who will develop OSA and when so as of now, no surgeon could in their right mind suggest an MMA for you to correct a problem that can't be diagnosed even though anecdotally we know that there's a good chance that in the future, when you're a worse candidate for it, you'd likely need it. Worse yet, we don't know how much to advance you to fix the problem because we lack the models. Fortunately, there's a limit to how much they can advance you in practice so that tends to be the number, no matter the aesthetic compromise. Some surgeons go by the philosophy of "making you look like everyone else", that is correcting the deviations, not making your airway as large as possible.
But to keep things simple, yes I'd say that's pretty small.