Ozzy, the only valid bench test is in unarmed state in Stabilize or Acro. The system expects different behavior in the other modes, and when armed, that can only be duplicated with a live helicopter ready-to-fly. For instance, in Loiter you do not have collective or cyclic control. The autopilot does. And you can do is make requests to the autopilot to move it or make it go up or down.
The only two manual modes are Stabilize or Acro.
Acro has strange behavior in Copter on a bench test. If you want to fly a greatly improved version of Acro you can load the ArduHeli 3.6.7 build from here->
The information on the new acro in the ArduHeli build can be found here and this has been a very, very popular enhancement for helicopters. There are some outdated links in that thread, but the latest version is in ArduHeli 3.6.7. There are several other features in the ArduHeli build as well, that Copter does not have. But you don’t need to worry about any of that stuff for right now, just to get your heli flying.