Can we get some terminology clarification here?
When I think "Feet up" I think "Feet in the UP/IN position, inside the keyboard" and "Feet down" as "Feed in the DOWN/OUT position, touching the table".
Not sure what usage some people are using here, seems to be a mix.
I'd say "feet IN or feet OUT" to remove vagueness.
That being said - feet in on my AT, feet out on M's (but sometimes in too, varies).