VTOL Not using channel seven. No rear tilt servo needed

I’m using a speedybee f405 wing. I need all 11 servo outputs. I am trying to figure out if I can use channel 7 for something else. It appears that when vtol is used it uses channel seven for rear tilt rotor. I have rear fixed rotor. I am using right tilt motor front and left tilt motor front . Is channel 7 unavailable to use?

I’m building a tri copter vtol. 2 front tilt rotors and 1 rear.