RE: Servos fully deflect at switch on
You need to Re BIND your plane and that should stop any deflection on start up.
It is recommended that after you program/reprogram any function in your TX you should Re Bind your RX.
I know of some people that will Re Bind once a month.
I do after what I mentioned above and during the winter when I am PMing my planes.
Try it and let us know.