I think they just title anything that's not an episode of a series as an 'OVA' to be honest, lol.
Strike Witches movie and Madoka/Nanoha movies would also be classed OVA's, or specials.
Fucking hated it when I found out these two were actually lovers. Thanks to the original dubbed I was turned off from all dubs because GODDAMMIT America ruins everything TTwTT
Anything released directly to video is an OVA, thus "Original Video Animation".
Well, I know and that's kinda my point - why would something released in movie theaters first still be OVA? I'm guessing in this case showing in theaters is more about promotion for video...