I’m having similar issues with this area. I’m trying to do a similar stripe on the nose as the decal file uses–nice clean smooth arcs. However, in this area forward of the pilot’s door, the line becomes wavy, and after spending hours trying to make my own stripe wavy out of phase with with what the UV map seems to be doing, I can’t get it to look right. I’ve wondered if perhaps someone has a UV map template that incorporates the decal lines as a guide?