So far you look good in both pictures. In the pre-op pictures the underbite is obvious.
In the post-op I do not see the problem. You look good. I also tried lining up your midline with your philtrum and it looks like they line up. So maybe something shows up on your xray but from the outside I don't see the misalignment.
I would just be careful about getting another surgery. The outside appearance is what matters so much, isn't it? There are a lot of people who had something wrong in their xray, went to get a surgery, and then the xray and the bite was perfect but they looked like s**t on the outside.
I experienced this with my first round of orthodontics. I had a palatial expander which lined up my teeth but it changed my whole face shape in a negative way. Originally I had a very delicate feminine face, but with the expander it widened the top part of my face but not the lower. So I now had a wider nose, weird looking midface, worse retrognathia...but my lower jaw and chin were still so small that I was disproportional. But my bite and xray were good! But it doesn't matter how great your teeth are if you feel ugly.
So with how good you look right now...I think if I were you I would just leave it alone. Just my thought.