karmov - 12:18 pm on Sep 15, 2004 (gmt 0)

Maybe I'm missing something here. Isn't a lower PR a downgrade?

Yes, a lower PR would be a downgrade, but there are over a hundred other factors that affect your position in the SERPs. If any one of them gets downgraded, your position in the SERPs could drop. PR is only a single factor amongst many. PR is not the only measure to go by.