Hi @Whitney Cook - Sounds like there is definitely a bit of confusion. Just to clarify, is the project organization currently a for-profit? It sounds like that may be the case but just want to make sure.
If they are a for-profit, you really need to be careful and clear that the specific work being done under fiscal sponsorship is actually charitable and is clearly segmented from the for-profit work.
Since Model C is really a regrant relationship, some sponsors do not assess a shared cost (aka fee) on earned income - only on charitable funds - grants and donations.
But no matter what, your organization, as the sponsor, should be the party that’s deciding what falls under the FS and what does not.