Can someone explain this table for me.

I am looking what would be a good spread for me and this table seems like it would work (from the BJ school) but how does the player advantage work?

It is the first table on this page... http://bj21.com/gamemaster/gamemasterclassics8.shtml

Is it that simple where for every 1 unit increase in the positive true count, the player's advantage goes up .5%?

So for a count of +7, my advantage is 3% and if the count was +14, I would have a 6% edge over the house? Is this the case?