Yes, the script is custom made.

When Adsense was on the site, I didn't optimize the ads at all. Also, the banner displayed at the moment is static, and if replaced with a rotator, could potentially earn 5x of what it is earning right now. In addition, if you look at the new UserCP design I had made up, there is a sponsored link that could go for probably $50/month if traffic were a bit higher. I had also planned a 125x125 ad on the new homepage.

BIN is justified by everything included with the site and traffic. Potential revenue also played a small role.