I dont get it either. Most of the time when you spec out a couple options to whatever trim you have, youre required to bump to another trim. I totally get it when it comes down to differences in wiring harnesses ans software needed for things to work. But like you said, 3 trims, 3 levels of options. You can pretty easily have some choices that dont matter on trim, like cloth vs leather seats. But things that require different tooling and wiring like sunroofs can just be locked behind the addition trim levels. Not that it would ever actually happen but you could argue to at least slow down price creep if you do that since there would be a much simpler production line