Kennedy Half Dollars

Forgive me if this is a perennial topic, but is there a reason why Kennedy half dollars are split into two entries either side of the bicentennial commemoratives?

Pages:
https://en.numista.com/catalogue/pieces65973.html
https://en.numista.com/catalogue/pieces6918.html

From the Red Book and various other research there's no obvious change in design between these two types, and it's different from how the Washington quarters and Eisenhower dollars are handled (they just skip the 1975-1976 dates):
https://en.numista.com/catalogue/pieces55.html
https://en.numista.com/catalogue/pieces1346.html

Thanks,
Pete

I think since they are different reference numbers, though I am sure you can make a case for combining the two pages.