Jim,

The two different ratings are foe using different jibs. PHRF allows a 6 second allowance if you use a #2 jib instead of a #1. So this is occassionally done in some races like shorthanded stuff. The fleet has decided to only race with a #1 (#2 not allowed) in one design races. This way the fleet remains a true one design instead of trying to use loopholes to win races.

Jason