When you calibrate, your not so much looking for the green bar to be green, you want your throttle stick at exactly 50%, like you made that switch. You hit "start", move all the sticks around moving the throttle to exactly 50% and hit finish. That makes naza see mid stick.........
you have to make sure there are no trims like idle trim at mid point or disable it all together and you want all your subtrims to read 0
So it doesn't hold an altitude as in put it where you want, hit 50% and there it sits, can be 53%, 48% and more so than just hold a height, it holds a height with cyclic input. in otherwords, once you got it not climbing or sinking, stop touching the throttle and move forward or to the side. it shouldn't drop like it would in manual. it can have a slight drop or rise when you go till you get a feel for not messing with the throttle at all. it's hard when your touching the rudder to fly around........