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

What's strange is that the values for RGB are fluctuating and aren't changing consistently. The only *mostly* consistent trend is that blue continuously becomes a larger portion of the overall value. However, even this breaks down as it goes from lavendar blue (very blue) to plum purple (balanced R & B values) to othard blue (again very blue).

These results don't mesh with the theory that fruits are simply adding to one color and subtracting to 2 others (or vice versa).