Comparison of algorithms for Fast Average Color

Num. Color 1 simple: (c1+c2)/2 sqrt: sqrt((c1^2+c2^2)/2) lab: →lab (c1+c2)/2 Color 2
1.
rgb: 0,0,0
lab: 0.0,0.0,0.0
rgb: 128,128,128
rgb: 180,180,180
rgb: 119,119,119
rgb: 255,255,255
lab: 100.0,0.0,-0.0
2.
rgb: 255,0,0
lab: 53.2,80.1,67.2
rgb: 128,0,128
rgb: 180,0,180
rgb: 202,0,136
rgb: 0,0,255
lab: 32.3,79.2,-107.9
3.
rgb: 0,255,255
lab: 91.1,-48.1,-14.1
rgb: 64,128,128
rgb: 91,180,180
rgb: 149,139,119
rgb: 128,0,0
lab: 25.5,48.1,38.1
4.
rgb: 0,0,0
lab: 0.0,0.0,0.0
rgb: 0,0,64
rgb: 0,0,91
rgb: 22,8,64
rgb: 0,0,128
lab: 13.0,47.5,-64.7
5.
rgb: 0,0,255
lab: 32.3,79.2,-107.9
rgb: 64,64,128
rgb: 91,91,180
rgb: 133,79,142
rgb: 128,128,0
lab: 51.9,-12.9,56.7
6.
rgb: 255,0,255
lab: 60.3,98.3,-60.8
rgb: 192,0,192
rgb: 202,0,202
rgb: 189,0,189
rgb: 128,0,128
lab: 29.8,58.9,-36.5
7.
rgb: 128,128,128
lab: 53.6,0.0,-0.0
rgb: 192,64,64
rgb: 202,91,91
rgb: 202,96,72
rgb: 255,0,0
lab: 53.2,80.1,67.2
8.
rgb: 0,128,0
lab: 46.2,-51.7,49.9
rgb: 96,160,96
rgb: 136,163,136
rgb: 118,161,104
rgb: 192,192,192
lab: 77.7,0.0,-0.0
9.
rgb: 0,255,0
lab: 87.7,-86.2,83.2
rgb: 128,255,0
rgb: 180,255,0
rgb: 174,255,0
rgb: 255,255,0
lab: 97.1,-21.6,94.5
10.
rgb: 255,255,0
lab: 97.1,-21.6,94.5
rgb: 128,128,128
rgb: 180,180,180
rgb: 202,138,170
rgb: 0,0,255
lab: 32.3,79.2,-107.9
11.
rgb: 255,255,0
lab: 97.1,-21.6,94.5
rgb: 255,128,0
rgb: 255,180,0
rgb: 255,161,0
rgb: 255,0,0
lab: 53.2,80.1,67.2
12.
rgb: 0,255,0
lab: 87.7,-86.2,83.2
rgb: 128,128,0
rgb: 180,180,0
rgb: 201,171,0
rgb: 255,0,0
lab: 53.2,80.1,67.2
13.
rgb: 255,0,255
lab: 60.3,98.3,-60.8
rgb: 128,128,128
rgb: 180,180,180
rgb: 201,178,162
rgb: 0,255,0
lab: 87.7,-86.2,83.2