SeaworldParksEntertainment in General (That is, Busch Gardens, Sea World, and affiliated parks) are sticklers for their seasonal stuff. As Platinum Pass member, I can get into any Seaworld park (aside form Discovery cove) anywhere in the country all year. I'll tell ya, they have very distinct season cutoff and do not change them once established, regardless of what Disney does. For Example, Seaworld will ot be doing Halloween until October, while Disney, universal, and both Busch gardens parks start in mid-September.
Unfortunately, Seaworld is just like that. Completely unbudging on a lot of things that the park fans would change. I'm sorry that it's become so disappointing for you.