IIRC there are SAG rules about this kind of thing where a voice actor may be used for at least one, but I think it might be as many as two or three other minor roles in an episode without having to pay them more. That's how you get things like Blum playing half the Stormtroopers on Rebels, or Lanter & Eckstein voicing random bar patrons or tactical droids.
In the case of Dee Baker though; given the sheer volume of characters he plays on a regular basis, that probably does trigger a higher tier of compensation than is usual, even on top of whatever the negotiated fee is for top billing and being 80% of the title characters.
In the case of Dee Baker though; given the sheer volume of characters he plays on a regular basis, that probably does trigger a higher tier of compensation than is usual, even on top of whatever the negotiated fee is for top billing and being 80% of the title characters.