Unit rates ONLY cover the written deliverable (outline, script) and DO NOT cover any work such as brainstorms, notes meetings, or the prep work required to attend those sessions (such as reading bibles, reading episode outlines or scripts, or watching episodes or animatics). TAG writers should be paid for any prep work you do in advance of a freelance episode, summit, pitch, etc.
You can read an explanation of prep work, including the definition, employer requirements, rates, and more in this letter that was sent to TAG writers by TAG Business Representative Steve Kaplan.