Harmy said:

That's strange - I've used the exact same settings for the AVCHD as for v2.0 and it came out quite a bit smaller (by like 600MB). This on one hand means, that I'll be able to add a few extra audio or subtitle tracks but it's a bit worrying.

That is odd, sometimes differences in colors and motion affect file size but since all the changes you mad were very subtly that wouldn't make much sense. Maybe there is a program out there that will crawl through a video file to look for corruption