Sounds to me like you need to re-program your ECU for your new expo settings. You exponential throttle is now not operating the way your ECU expects (ie your trim lever no longer has enough "throw" to control the ecu functions).

Also, I would recommend actually using a helicopter style (multi point) throttle curve as opposed to exponential. These exponentials normally have effect around the center of the travel, which is not what you are looking for. You need the multi point curve function. Maybe these radios have something like multipoint on throttle expo, I am not a radio expert by any means.

I posted a picture of this curve further up in this same thread.

Good luck