I would lower your prices...
your stadium is decent size, but well worth growing.
My suggestion: 400 for the box seats
70 for the courts
28 for the second tier
10 for the bleacher
Expand bleacher only.
See if you sell out other sizes, if so expand those.
Expand bleachers 1000 for now...then expand the other sizes if they sell out.
Do the math as if you sell out. See if you would make more money. If you do that is good! That is the math.
But if you make a little less, still OK but you expand more then. You see?
GL!