Jerry, take a look at the first two pics in this article. (In fact, I recommend reading this article)
http://www.manzellagolfforum.com/forum/topic.asp?TOPIC_ID=222
Pic1 is standard address: left wrist bent (toward target) and right is basically flat.
Pic2 is what you want to use throughout the rest of the swing, and some people use that hand position EVEN at address (which would be called Impact Fix hands). Notice the hands in Pic8 are like Pic2, but now at impact.
Your question was about cocking the left, which is a motion "up and down"..and as you've heard it can be done at a variety of places in the swing, early or late, gradual or more abruptly.
So hopefully you are learning the difference between bending and cocking.