There can be usually multiple patches. The dates on the patches are the day of when the patch has been compiled. I noticed once that they increase while downloading and installing. So basically we are patching the patches as well.

I just wish that the pause/resume on download was working, though. I had a couple of PSN disconnection and it had to start all over again for 3 times!! And with my connection it means 1GB per hour. Plus the fact that I wasted 3GB of traffic quota on top of the patch (out of 15GB per month. Yeah, don't tell me).