I put my vote in for "no positive gain" .... simply because both the original Color-C-lector and the Combo-C-lector that I've owned, only showed me basically one color combo to use in all the years I used them.
I used them back in my early Bass fishing days, but only fished one particular lake, and already knew the color combo that the unit suggested was a good choice ... that being blue/chartreuse.
It may also be the reason that the color combo I started Crappie fishing with (for plastics) was blue/chartreuse.