FQ, There is one major difference, in all the other cases we are talking about "Territories". But in the case here, and with WVa and Maine, it involved changing an existing "State". Territories are land the country owns that is not particularly settled, or organized, it can be adjusted and modified with out effecting anything else.
When you start screwing around with States however you are effecting Nation issues by changing the numbers of Representatives and Senators .