You are grasping at straws.
You tried this sort of argument before, it was debunked easily:
https://www.theflatearthsociety.org/forum/index.php?topic=70614.msg1916123#msg1916123
Well, i didn't expect our conversation was going to end up (be so akin to...) like this :
Dr Robert Sungenis vs Allegedly Sane Flat Earther (hilarious excerpt) :
This would matter if Australia existed - flat earth for dummies :
FLAT EARTH PROBLEM (LISTEN IT VERY CAREFULLY) :
We were talking about MGPX, remember :
ASSERTION NO 1 :The system of interference-fringes produced by the superposition of the two pencils-one of which has traversed the circuit clockwise, and the other counterclockwise-would be shifted through seven-tenths of the distance between the fringes, in the direction corresponding to a retardation of the clockwise pencil, if the experiment were tried in the Northern hemisphere.You see, we have to deal with a degree of retardation of the CW pencil (which is smaller in the northern hemisphere) wrt a degree of retardation of the CCW pencil (which is greater in the northern hemisphere)...
So, if both beams were to be retarded then how would we get the difference in the speed between two beams (both beams travel in both directions (one beam goes firstly right then left, another beam goes firstly left, then right), and both parallel tubes are of the same length), that is to say, what would cause fringe shifts if both beams were to be retarded?
To be perfectly correct we have to admit that both beams would be retarded, indeed, however :
CW beam would be less retarded, because going along southern tube (in the northern hemisphere) CW beam would go in the same direction in which aether flows...
CCW beam would be more retarded, because going along southern tube CCW beam would go in an opposite direction wrt the direction of aether's flow...
That is what makes the difference (which beams goes with or against aether's flow through the tube along which aether's speed is greater), if you think that you can point us towards some other cause (mechanics) of fringe shifts,
let us know...