Wouldn't it be possible that at least after opening the GSX menu the aircraft automatically is repositioned e.g. the xxx.ini file is read and excecuted?
We could even do this automatically without opening the menu, basically auto-warping to your custom position automatically. However, this will be risky because, what if you made any kind of mistake editing, so your custom position is now placing you in the wrong place, like inside a terminal or a place you could crash into ?
With the way it works now, you can easily realize that, because you'll notice the positioning is reasonable (it's default) using the MSFS menu, but had issues with Warp Me but, at least, you would have a *chance* to fix it, because you got there with the MSFS menu and could fix the position in some way, for example by resetting the parking in the 2D editor. But if we auto-warped you, and there's a problem, you might end up slammed into something, possibly crashing the plane, with no easy way to exit from that situation. So, the MSFS default position can still be useful to have.
Note that, there is already an "auto-repositioning" function: if the MSFS position and your custom one are too different ( I believe the difference must greater than 20 meters ), when you start a service, GSX WILL prompt you to auto-reposition there, because it suspects there might be issues starting services when you are parked in a position that is too different than the ones you set up in the GSX profile.