> As you can see from the recent books FMS is not
> losing any listerners, so Hank has to be pulling their
> listeners from other stations.
No, that's not how it works. The amount of radio listening that occurs is not a fixed number -- the "pie" of radio listening can grow or shrink. In this case, "Hank" has likely created listening that was not being done before it existed, giving them some numbers while not necessarily hurting others as the total amount of listening is grown.
Funny things can happen as the total amount of listening goes up or down. If listening goes up, it's possible that a station's share could go down while the actual amount of listening garnered by it would go up! Conversely, if total listening goes down, it's possible a station's share could go up while its actual listening went down.
Anyway, it's not necessarily the case that success for one station means loss for another.