Eflite mini apprentice ar636 proplems

I added flaps to my mini appretice and it worked out great..just used balsa wood and double servos off a y-harness. The problem i encountered was when i fully opened the faps past past 30% or so all my surfaces wouldnt move but slightly..unless i moved it back below that threshold the as3x and all flight modes would be limited to very little movement. I ended up putting the reciever in my super cub and reprogrammed it for the turbo timber settings with the spektrum software and it works perfectly. Im going to put another ar636 in the apprentice when it arrives but this problem might come back and im stumped why this happens. I use channel 6 for flaps and i hope ill find some way to get full deflection with the rite setup.