Rush's guy backed up his claims with real numbers. Media Matters has been caught in outright lies more than once, so take all of both sides with a huge grain of salt. The truth is more like Rush improved some really bad stations, but they're still in rough shape.
If people are just discovering his new station, it's easy for "Rush's guy" to boast an increase of 230%. Starting from a minute base, you can generate some pretty phenomenal percent increases to a plateau that's still small. Anyway, that's not the point. Rush's guy has to make lemonade from his boss being bumped from a big station to a small one, which was not without cause.
Holland Cooke is a good reference for Rush's decline in audience.
http://hollandcookemedia.wordpress.com/