I expanded my arena quite a bit in the beginning, so I couldn't set too high prices. But even after expansion the first 6 games, you can get 15 for bleachers. The fans are euphoric after promotion, then when the hiss stops, 11 would be more reasonable if you lose most of the games.
It'd make sense to set the seat prices proportionally to their costs i.e. if
15 bleach, then
53 lower (15*(700/200)) and so on..
Say you only fill 6000, *15=90000. That means there's no point setting prices lower than 90000/6500=13,85 and even then, you'll only get 14*6500-9000=1000 more. I do believe you could fill 6000 bleachers à 15 for the first 6 home games regardless of your results.
Good Luck!