I thought of that to, there is a table on the back, but its not affected by the switch in any way I can tell. Although to the right of the switch is what appears to be a sensor of some sort. I'm guessing that it affects the sensitivity of that sensor. The colors meaning distance. It was a cheaper lens, promatic/promaster isn't known for expensive and quality, but for $10 I was willing to take the risk for a swivel flash. The flash also has a fill in flash on it.
I just wish it was easier to find info about it.