I know that also my "balancing" will have some things that will not fit perfectly. But I can change it if I think it is not good. Probably I will even change things when somebody else says, that it is wrong.
I take it the other way round. I add folding seats full and standing places at a 1/3 rate. And I also define these passengers, because I think a commuter bus or train must have standees when it's full.
Anyway ... I will release my script and everyone can make his own changes.
And finally about the tga/dds conversion, i think that there is more than lazyness. I have a photoshop licence at work i can use to convert textures, but i haven't found a way to have *working* dds textures without it (i couldn't get any of the alternative to work for all types of textures). And photoshop is certainly not free, so i can see why people stay in the TGA format.
I don't own photoshop and I converted every .tga to .dds. Mostly with paint.net, for the normals with GIMP. Both programms are at no costs ... it is lazyness. Not installing a programm or finding out how it works is kind of lazyness too.