As to Frise aileron - Frise's design is a very specific geometry to achieve a protrusion of the aileron's lower edge below the wing to add drag when the airleron is up, and minimize adverse yaw.
This would be Frise's classic design, with pivot point well back (~25% chord), and near the
lower wing surface:
http://accrodavion.be/Accrodavions/i...on%20frise.gif
However, there are
other geometries that can achieve the same thing (leading edge dropping below the wing for drag with up aileron) - even with the hinge near the top. This geometry looks - schematically - a bit more like what the 172 actually has:
http://aeronotes.weebly.com/uploads/...457099.jpg?243
It gets to be a matter of semantics as to whether "Frise aileron" and "Frise-
type aileron" mean the same thing or different things that achieve similar ends. I'd say the 172's ailerons are clearly not authentic "Frise ailerons", but may impart some (non-zero, even if negligible) drag when up, to balance the induced drag from lift on the other side.
Technically - this is a C-150 aileron:
http://www.cessna150.net/Assets/Phot...on_weights.JPG
As to differential, again it is a question of naming techniques - or outcomes.
The sloped leading edge of the Cessna aileron:
http://hangarswap.com/image/data/Han...8/IMG_0384.JPG
means that the top chord is an inch or two shorter than the bottom chord. So even if the
deflection in degrees is the
same up or down (about which I know not), the "up" aileron will present a slighty smaller surface area (chord x span) than when "down". Thus achieving differential
aerodynamic effect without differential deflection.
Been a while since I flew a 172 - can't remember how much adverse yaw it demonstrated.