"Sold premium tickets significantly raise a show's gross, it doesn't have an effect on its attendance."
That's not the issue. The original question asked how a show could exceed 100% of capacity. The answer is that capacity is based on the face value of the ticket (e.g. $147.00), and not the sale price of that ticket at a premium (say $350.00). That's how popular shows sell over 100% of gross capacity. It has little or nothing to do with standing room.
CZJ at opening night party for A Little Night Music, Dec 13, 2009.