in slug 32: (before the beam optics) one slope file is for both arm data; the other is for single-arm data. in slug 33: (after the beam optics) the slope file is for single-arm data. In slug 33, did you find the mean for regress corrected plots is very larger (10^1 order) than the normal case by a factor of 10 - 100? Normally it is 10^0 - 10^-1 order. Attachment 1 : w/o dither / regress corrected Attachment 2 : w/ dither corrected Attachment 3 : w/ regress corrected P.S. (post-script): I changed the color code, so that every of cycles, where one cycle includes nine dithering slope groups, has the color codes (0: black (default), 1: red, 2: light green, 3: blue, 4: yellow, 5: pink, 6: light blue, 7: green, 8: purple, 9: brown(the cycle is finished here.)) which are more vivid. SetMarkerColor(i%9+1).