You don't skip the final FMV, which counts for IGT. PAL gets a big advantage here.

It doors didn't count, it would save 20 minutes approximately wouldn't it?

I kept entering and exiting a door near the end on GameCube PAL and the IGT result was considerably slower.

PAL is already separated if you use the region filter.

PAL's IGT is faster because the FMVs move the same speed as NTSC, but only 50 frames pass. So the FMVs are approximately 16.67% faster to PAL's IGT.

So if the FMV spends 60 seconds IGT on NTSC, it will only spend 50 seconds IGT on PAL.

Also, because some of the voices were used to synchronize cutscenes, PAL cutscenes will spend less frames overall on those cutscenes, since the voices will finish playing in less frames. I don't think GameCube's cutscene skip is affected.

You also get more reaction time on PAL, so the slower version gives a better IGT.

You can kind of tell what the PAL time would be on NTSC if you account for the final FMV, plus some more seconds for cutscenes.