My point is that your conclusion that they pay DOUBLE the rate is entirely based on this number that you give no justification for. If your comment started with "Lets assume each AM/FM broadcast went out to 5,000 people," then the rates would be roughly the same. So yeah, you can assume that number is true, but what's the point.
In principle you have a point, but a quick google shows that his number is entirely reasonable. I mean, I wouldn't read to much into the exact numbers here, but the scale is definitely comparable.