The previous fan docs were pretty screwed up. The now-banned individual who put it together re-encoded everything to PAL specs when it wasn’t needed. So anything that was archived probably could have fit together in a different way. It really is too bad.
I can’t speak for the individual you refer to, but when I authored the second and third volumes of Alien Appendix, I needed to reconcile a mixture of sources - some NTSC, some PAL. Since the longer pieces were from PAL broadcasts, I prioritised those.
That was the way it was in 2007. These days, I naturally wouldn’t use DVD media, but even BD video has its issues - you could theoretically combine both SD NTSC and PAL on one disc, but most US BD players wouldn’t be able to handle the 25 frame content (I don’t know if UHD players/displays have moved forwards in this respect).
I guess the only solution that would suit all users is the ‘bag of files’ option, which isn’t much fun from a user perspective but at least has the benefit of source purity.