Have no idea if the rating is correct or not. I don't race normally. when I did race I sailed one design (S2 7.9), so never got into the ratings. I know they gave me a break because I had a furler, dodger and Bimini.
I have a full batten main with a 155 Genoa (furling). Sails are two years old. Never could flatten the boat with the old 20 yr. old sails. I picked up 1/2 to 1 kt. when with the new sails.
Speed was COG sailing in Lake Erie, may have had a little current at the start of the broad reach due to shipping channel, but maintained speed from the Detroit River light to Toledo horn.
AS they say that's my story and I'm sticking to it