Financially speaking, 5th is waaay better than 6th. Not only do you not have to pay salaries, you still get the merchandising and TV income and means you usually churn a profit.
in 6th, you pay salaries and you get extra games but you probably won't be able to make up the shortfall of not having to pay salary to begin with. Also, an implication people don't usually consider is the next season. Teams that finish higher earn more cash by having a more fan support so in the long run, its always better to finish higher.