Jim, here's my non-Golfweek rater's understanding: a "Golfweek 10" is a top 10 course, a 9 is a top 25, an 8 is a top 50, a 7 is a top 100, a 6 is a top 250, and so on (hope my memory is okay on those numbers, I think I'm at least close). So, by Bill saying it's logarithmic, he means each drop in one digit, means a bigger field of courses in its category.
As for why the lists don't mesh, you are only comparing the courses to their time-peers; in clearer terms, you might feel a course is top 10 for modern courses, but only top 50 when compared to the Pine Valleys and Oakmonts of the world.
Hope that helps.