It is defend upon to your signature campaign example the rules of your campaign is maximum of 20 post per week. So per day you can post 3 post per day to avoid conflict in your campaign because some campaign cannot allowed to post in straight maximum post in 1 day only. So time management must be apply.
That's not true, if they cap your posts at 20, it means they only want to pay you for the 20, and not beyond that. I've posted over eighty posts in one day, I have also posted no more than twice on a given day, it has no bearing on how they perceive your posts as spam, it's about the content, not the quantity.