Jeff - I presume you mean that dynamic stability (boat in motion, seas in motion) may be quite different from static stability (boat at rest, seas still - how far can you tip it over and have it still pop back up), and you may be alluding to the studies that show that regardless of the stability ratings, basically the larger / longer the boat, the less it is likely to capsize . . . yes? Probably this question been discussed ad nausea in other threads, so we can search for them.
Even so, perhaps the numbers may still be of use as a means of comparing the likely stability of very similar boats to each other?