Woodbridge>
I tend to think of expansions differently. At first I thought as you did that the higher the price the more you want of the seats. But then it dawned on me. If you sell 100 seats for $200 per that's 20,000. If you sell 200 seats at $120 per that's 24,000. So 4,000/100 =$40. So each extra seat from 100-200 = a profit of $40 per. It will take roughly 50 weeks to get back the initial investment if the seats cost $2000 each.
The only time when you get a better return on investment is when you are selling out. If you are going to have 2-3 more weeks before you can change prices, then when you build you will get an immediate return on investment for whatever price you sell for for a few weeks until the next price adjustment. So for example I added 1200 bleachers at 200 per. Because I was selling at 10 each, I was able to take a week where each extra seat earned 10. This is 1/20th of the original investment.
The predicatability of courtside and luxury box seats makes it better to build these early IMO. That way you can set the price easier and be close to selling out or selling out which is what you want.
Arena expansions only pay for themselves if the pricing is accurate. If you over/underprice considerably than it takes a lot of the gains out of the expansions.