In the install manual for my F500 (which is pretty useless as it doesn't cover half the stuff, and crosses over with the other manual), it says to unscrew the bolts holding the oval plate on at the top. This would mean that just the plate just floats, with only its weight closing the gasket. This seems a bit unintuitive. If there was just one, easy to read manual, I'd trust it, but...
Do other F500 users have this plate floating?
Do other F500 users have this plate floating?