mglavin,
In case you haven't seen my posts, then FYI I'm on your side of the fence.
However, I think the statement above is false. If you look at post 54 you'll see that I've included a quote from Mike McConville on Flying the FuntanaS 3D .40. He uses what he calls coupled spoilerons and snap spoilerons.
I do agree though, that the mixes used will be model dependent. For example, on models that have two elevator servos, I've heard that the elevators can be used to work in conjunction with the ailerons to increase the roll rate. Would this be "coupled elevons"? I've not heard that term used, so maybe I should copyright it

So, my point of view is that many 3D/aerobatic guys might use all sorts of coupled mixes to facilitate certain maneuvers, but they are either too lazy to assign a proper name to the mix or want to keep their 'magic' radio programming a secret thus reverting to the ambiguous (incorrect) term flaperons....