Hi Slyskydogg,
An Offset mix (when Offset is master) will activate your slave channel a fixed amount. This gives you a changed Neutral position to the servo you have chosen. This offset position never varies, and it acts kind of like a snap roll or engine kill, but it can be used on any channel that has an on-off switch.
Null, is just what it sounds like, when you have a mix set on a switch and you set the switch to Null, the mix is always active, and can never be changed in flight. So the movement of the switch is "null".
I hope you find this information helpful. You can also reach our Futaba support technical team at 217-398-8970, or via fax at 217-398-7721.
Sincerely,
Krysta
Lead Futaba Customer Service and Programming Technician
Also you may want to check our Website at (
http://www.futaba-rc.com)