Normally, a flaperon wing type is used with planes that have full span, strip type ailerons. The function does allow both control surfaces to move together as flaps or spoilers and opposite as ailerons. You normally plug the right wing servo into the aileron channel and the left into the flap (ch 6) channel. Once a Flaperon wing type is selected, the controls work. You will have to set the amount of flaps to move if you want them to move with the elevator.

For a scale Cessna, I would imagine you have ailerons at the outer part of the wing only. If you set flaperons with them, you will be getting wash in for landing. Your tips will be at a greater angle and tend to stall first.

If you have separate flaps, you can set elevator-flap mix to use them in maneuvers.

One use of the flaperon wing type is that it allows you to adjust each side of the plane individually-sub trim for centering and end points. I use it for this on every plane, but rarely use a maneuver type flaperon. On fun fly planes I do reverse the flaps and use down flap with down elevator. It helps in waterfalls and flip-flop type maneuvers.