A frequency analysis test would give you the answer. There was a test done before on the SansAmp Bass Driver DI (BDDI) in trying to figure out where and how it scoops the mids. Very informative stuff. Here's the thread:
Semi-Scientific SansAmp BDDI Analysis
You could use a similar approach as scotch to figure out what the Color switch is doing. Analyze a flat signal from the M-80 as your control, then press the Color switch, and analyze again.
BTW, if you happen to perform this test, be sure to post the results!