Netural and center can be two different things. I consider netural to be when the servo is not driving in one direction or the other, and Center to be where the servo throw in mid point between the extreames. I know that the term netural is used as center, but if your throttle is set somewhere, the servo moves to match the stick and at that point it goes into netural, not driving in either direction. All the other servos will do likewise, but other than hands off the stick or jamed to full travel on the stick, the servo is generally following the stick movements. When the stick is centered, the servo is centered, and in netural at that point. No mater what the trims are set at. You trim to find center.

This is just my way of keeping things straight in my head.

Don