I can confirm they are different. It's a bit confusing that way, but if you donated through button instead of account upgrade you can PM Diana to request your fancy banner anyway.
Yeah, I wish they -weren't- separate, but the Donation Mod creator has not connected the features yet. O_O (and we don't know if they ever will or can.)
The link to the upgrade/donator account section is ALSO linked on the donation page. 8D So you can find it that way too. And yes, if you use the donation page but also want the green donator name all you have to do is send me a message and I'll add you in there.