IGC files have pressure and GPS altitude. I can see both of them in SeeYou. Here they give the same results, but that doesn’t mean that the altitude shown on the 6030 display is the same as the one displayed later in SeeYou (or FS, for that matter). I’ve seen huge differences there, and it doesn’t matter which altitude SeeYou is displaying.
I believe that SeeYou adjusts the altitude displayes to the terrain. It moves your launch altitude to match the take off spots altitude as it knows it and then adjusts everything to that altitude. I don’t know if FS does that also.
I just wonder if FS or SeeYou can be used to provide the altitude that the pilot actually saw displayed on their 6030. I very seriously doubt it.
Which one is right?