This is a well trod path. There is often little connection between the number used as a label in the model name and a real measurement. Model names using numbers are chosen to position the boat both in the minds of potential buyers and as a comparator with competitors. In a previous age before "size" became important as a measure of position on the pecking order, LWL was the most common way of describing a boat when aimed at the racing market (because rating rules used LWL as a base) or TM as a measure of volume for cruisers.
As we see from Kala's dilemma, rule makers set their own measures if it suits them and for obvious reasons it is in metres and because rules require authentication they will look for an "official" confirmation. The silly things is that they are using the 11.5m as a proxy for some idea of capability of the boat that somehow makes it suitable for a particular use, when the RCD category already does this - and is indeed often used in countries that are obsessed with rules. Using the same logic, if the threshold was 10m, my 33 would not comply because the maker says it is 9.99m, but neither would its predecessor which was called a 32, nor its successor which is called a 34 - even though they all have the same hull!
