Look at the 'Formula 16' rating, there is no separate rating for each design, there is just one rating of the box rule (interesting, knowing that the box rule doesn't limit the daggerboard area and that the area is necessary for the rating calculation...).

Anyway SCHRS values:

F16 uni 0.982
F16 duo 1.008
F18 1.005

Why isn't there two rating for the F18, one for the "big" rig, one for the "small" one is beyond me. Scooby can probably explain.