Understanding RC calibration

I’m trying to understand the meaning of the RCX_MIN, RCX_MAX, and RCX_TRIM parameters. Are these parameters applied to the inputs, outputs, or both?

For example: I have flaps on channel 7 of my transmitter, and channels 7 and 8 on the pixhawk are set to 3 (auto flap).

I need to adjust the RC7/8_MAX andRC7/8 _MIN parameter to get the servos to center up properly. I also need to invert one channel for proper operation. By changing these values I can get what appears to be correct operation of the flaps.

However since I’m using channel 7 as flaps from the transmitter does changing the _MIN and _MAX parameters also affect the calibration of the input channel value? i.e. with the surfaces trimmed is there a chance I am reading some small flap percentage being commanded?

I’ve noticed when I do an RC calibration the _MIN/_MAX/_TRIM parameters change for channel 7, even though they appear to control output values as well. Suppose once this plane flies I want to recalibrate to reflect trim changes for roll/pitch/yaw, do I then need to go back and manually enter my previously determined values for channel 7/8? Can someone please explain how all this works?