There is no visible, discernible delay between channels, when you assign the channel NUMBER the same "name"....i.e.. I have my Right Elevator on CH 6, identified as "ELEVATOR" in the CHANNELfunction. I set up the Left Elevator on Channel 7, identified as "ELEVATOR" also.
Now, the individual channels sub trims, end points, are adjustable in the SUBTRIM and EPAmodes.....but in D/R, EXPO, and all MIXES.....BOTH channels get affected simultaneously.

I tested this doing a R>Elev mix, permitting Trim to affect it..... you cannot see ANY difference in timing on the deflections.