Just to be clear, you can but you'd have to make two seperate accounts. One for fan fiction, and one for original work. This is because ad rev is for your account, not per series.
Support is separate from ad rev. The support system is derived from tapas ink, which users can buy or earn for free. Ink can be tipped to a creator with support set up, and that ink support translates to monetary support. In a nut shell.
So there is a potential for money either way, and you can obviously put a link from one account to another if you went that direction, but it does have it's issues.