I calculated the ratio between the absorption measured at LMA and at NAOJ.
Since the maps were not exactly overlapping, the ratio showed the same structure of the absorption maps.
This is because the center of the mirror in the two systems has some mismatch.
To find the best overlap of the maps, I calculated the ratio in a loop where at each iteration the two maps were shifted with respect to each other.
I calculated the standard deviation of the ratio map and I found a minimum of the standard deviation for a shift of 0.6mm along X and -0.6mm along Y

the ratio is 3.0 +/- 0.8 (average and std on the map)

I plot  also a histogram of the ratio