Right, but I think that the multiplier could increase in value after the jaw surgery.
LEt's return to the Gaussian:
View attachment 86671
And let's assume that the LL surgery buys you, say, 0.50 point, for the sake of convenience.
If you're currently at -1.50, then the LL surgery will take you to -1.00 which will not yield you substantially benefit. However, if the jaw surgery is twice as valuable as LL, then it will take you to -0.50, and the LL surgery can then take you to 0.00.
The jump from -0.50 to -0.00 is far more valuable than the jump from -1.50 to -0.50. It's actually roughly 0.1915/(0.9332-0.8413) ~ 2.1x more valuable.
But let's forget specific numbers. The point is that for someone who is below average, I expect separate facets of looks-maxing to amplify each other.
Leg lengthening surgery is of course still out as you cannot quit your job for a year, but the jaw surgery could, for example, increase the prospective yield of body recomposition.