Well, to kinda close out this thread and provide the right answer to anyone else with this question,
I experimented this weekend and determined that the Look instructions I downloaded off their website are WRONG! I turned the adjustment screw in the direction of the minus sign, and the tension loosened, which is the opposite of what the instructions say. As I was turning the screw, I could tell it was getting looser. Sure enough, when I clipped in, it was much easier (I loosened the screw until I was afraid it would come out). And, when I then tried to un-clip, it, too, was much easier. I can now get out of my pedals with very little effort, and yet my feet didn't accidentally slip out while pedaling. I will probably tighten the tension somewhat after I get some more riding time, but for now, I'm much more confident when I approach a stop!
So, it anyone else has the Look pp206 pedals, the tension adjustment works the way you think it should by looking at the plus and minus marks--NOT the way Look's English instructions say it does, at least the instructions I downloaded from the Web. My lbs installed the pedals when I bought the bike, so I don't know if there were any hard-copy instructions with the pedals or not.
Hope this helps someone.