In the 7C transmitter, slave channels of mixers don't get the benefit of the trim of the master channel.

The Throttle Cut function only works with the throttle channel. In fact, it only works that way in the 9C. In the 9C, to get a second channel to cut when you flip the switch, you have to use an offset mix set to the same switch on that channel.

All this is on the FAQ page for the 7C system.