As much as I wish your statement was true, and I have seen people here say the same thing for years, it is simply not true.
You cannot tell from Level 2 how much is for sale at any given price, you need Level 3 for that, and we peons don't get that.
Any market maker can have any number of bids or asks on the books, but we only see their best on Level 2.
For example, CDEL has 15,000 showing for sale at .084 right now. They could have asks at .085, .086, .087 and on and on, that do not show, only their lowest ask shows on Level 2.
Level 2 is a good tool, but not perfect.