Chocobo Dye - The Missing Manual

[Giantbane]

My FC has been experimenting with O'ghomoro berries only (deepen blue hues). If they stop at color change, they have been able to repeat the results multiple times. This is the path for the berries:

[197,139, 79] - Cork Brown
[178,157,105] - Ul Brown
[180,158,130] - gobbiebag brown
[140,122,101] - Shale Brown
[130,128,125] - Goobbue Grey
[128, 120,169] - Lavender Blue
[114, 75,101] - Plum Purple
[ 41, 81,130] - Othard blue
[ 34, 42, 96] - Royal Blue

And berries stop doing anything after that

Problem is that all of the RGB values are fluctuating and there isn't a consistent increase or decrease to anything that's happening. How does the manual explain this transition?