Your table assumes that performance is linear in the range of B2-3 and I think that is a problem.

Your deltas seem reasonable for B3 (7- 10 knots or 7.5 to 12 mph) but way off for B2 (beach cat's to mono's.)

The modern high performance cats should be able to fly a hull at 8 or 9 knots (B3) upwind and down wind and sail to those ratings. However, at B2 the beach cats are stuck in the water and I doubt they can sail to the ratings you list and so one rating number for this range is off (one way or the other).

I suspect the B2-3 band was useful when the majority of boats were Hobie 16’s, 18’s etc and indeed their performance was much more linear in this range.

Did you consider wind ratings bands of 0-2... 3-4 and 5 to go home?