It looks to me as though they instituted a cap of sorts. I had an even 18,000 bleacher bums show up, which just seems odd if there isn't a cap. As far as lower attendance, I would guess they're more targetting the outrageously huge arenas by that comment. I haven't checked but I'd be somewhat suprised if any of the 40k+ arenas sold out.
You had a sold out arena, but your prices are also on the low end as well, so I'm not suprised at all with your result.