Thanks Sotiris, that isn't quite as detailed as I think I'll need, but it's a good starting point.
I suspect that a lot of the problem people are those that haven't flown since the FAC update and their scores swing "wildly" from their old to new...
As an example, my own score is -7595.1. If I fly the entire Orient Express event online (assume 2hrs per leg, 0 new penalties) my score after each leg will be:
Leg 1 -7557.7
Leg 2 -7520.3
Leg 3 -7482.9
Leg 4 -7445.5
Leg 5 -7408.1
Leg 6 -7370.7
Leg 7 -7333.3
Leg 8 -7295.9
Leg 9 -7258.5
Obviously, can't test this for real until the OE event

If you have them, can you let me have pilot IDs (esp. your case #1) either by email or PM/Management Forum.
EDIT: and case #3 is entirely possible in the new FAC scheme assuming a *really* bad flight... Another direct example, assume I've flown 2 1hr PP flights, one online, no penalties, my FAC will be 37.9. I'm doing so well, I have a go at a 2hr online PP flight and make a right hash of it - 1000 flight penalties, want to guess what my new FAC is? -924.7!