with differential, you should have more up deflection than down. I'm not sure why yours is the other way around, but I think you should resolve it before flying. There may be some serious adverse yaw effects there. Make sure you have the correct ailerons hooked into the correct channels--which depends upon your brand of TX. You must hook the aileron servos up correctly each time, or you will have problems--out of control problems. This is the downfall to not using a Y harness. For a few bucks, you could get a Y harness and just plug one plug each time, and not have to worry about whether they are backwards or not....