its not all about the amount of travel when you use retract servos there is positive up and down locking, without loading your battery and running it down during flight, the amount of travel can be adjusted in the servo arm as you know, I am surprised you are getting so little travel from your servo, check your end point adjustment for your retract channel some radios have power on power off for this channel, depends on your set up you should be getting more travel.
it sucks having to spend 30$$ on retract servos but you will be better off for it