I think this will probably get right to your question. The carapace size is related to trying to have at least 50% of the females spawn at least once before they enter the harvest. That is the main and ultimate goal, if you want to look at a progressive stage.
When you look at page 20 in our book, you will actually see a graph of how close each area is and how to determine what would be needed. It's economically crippling if you move in too-big increments. This is the whole idea, to try to move people along a gradualism.
In some areas where you may be farther apart, you may see other management measures that are in place, like protecting the large females, which certainly produce a hell of a lot more eggs. You may have a size measure that produces something that's five inches and up. Well, that group may not have the goal as tight to the 50% level as someone who doesn't have something in place to protect the....