You probably just have the top aileron servos backwards. Rotating it 180 degrees on the correct axis should fix it. I'm not exactly sure how to describe which way you need to turn them, but you can probably figure it out. It is similar to how flap servos are placed in the same orientation so that one isn't backwards.
Around 14:42 in the video pause it and you will see what I mean. One of the inner flap servos has been turned so that both flaps go the same way. All you need to do is flip around the top 2 servos in the same way that the flap servo was flipped. If you don't see what I'm talking about, compare the flap servo orientations relative to each other to those of the aileron servos and you will see what I mean.
Alternatively, since you will probably need to pull the servos out anyways (unless you can do some magic with extra channels or servo reversers) you could just remove the servos permanently, cover up the spots where they were, and set up the ailerons the way they should be. You would be saving yourself some weight and complexity while also putting less load on your BEC. I don't see how it could be any worse than the current setup, and it should actually be better.
