Without records I can't say for sure, but at face value yes it does seem crazy to get jaw surgery for 3mm impaction only if everything else is fine.
I understand. The issue is my mouth looks too low on my face now, something genio cannot correct. I believe the uncanny look is, to an extent, independent of my longish upper lip. Meaning, 3mm impaction will address the issue while I obviously retain the same philtrum length but lose the "long face" look to a satisfying degree.
On the subject, I notice men with long philtrums (eg Harrison Ford) look good only if the long philtrum is not accompanied by a long maxilla. This is where I get the idea that limited or no teeth show (at rest) is preferable for patients with long philtrums and surgeons should make the distinction for optimal pre surgery planning.