Individual thruster control

I have previously shown interest in controlling all thrusters on the blueROV individually.

I eventually just tried recompiling ardusub with a custom frame where each motor has a single degree of freedom.

When I uploaded this and changed the configuration to custom in QGroundControl, I tried to command a single thruster and I am still getting multiple thrusters firing even though they should all be decoupled. I confirmed by looking at RC channels in the analyze section of QGC that only one channel was being changed from 1500

Any idea why this may be?