They are for 2 distinctly different flyig styles.

The case where the elevator and ailerons move in opposite directions is an attempt to enhance speed of rotation for tight loops and more snap in stall maneuvers.

The case where the aileron and elevator work in the same direction, and usually activated only just prior to landing is an attempt to be able to hold the nose higher, to slow down further for landing, and still not stall the wing. This is sometimes mixed through the flaps channel instead of elevator, and if you've got the separate flap surfaces, they'd go down as the ailerons moved up.. for what is called "Crow" or "Butterfly" mode. (a variation on airbrakes)

Without knowing what you are trying to do... and which model you want to use it on.. can't advise if you want ne or the other... or neither. If trying AMA Pattern precision aerobatics... MAYBE the latter, but never the former. If doing 3D... could be either or both.