Are you sure that 1010 actually beat 620? I don't see how 1010 who hasn't shown up can leapfrog the powerhouse. Do you have proof?
The only numbers that Arbitron releases directly to the public are the 12+ which shows WDAE at 2.4 and 1010 at 1.0 which is nothing more than eye candy. The key demographic for sports is men 18 to 34 and that's historically where WDAE has cleaned up. I could be wrong but I understand that 1010 when was able to beat WDAE in listeners (men and women) 18 to 34.
Unless someone slips a book to the newspapers all you're going to get is hints over the air from the winners of certain demos and echos on message boards like this one (along with certain shows disappearing without explanation).
One thing to keep in mind about these boards is that no one has anything to gain by lying and the truth is known by enough people for the truth to come out, even if you have to read between the lines and do some extrapolating.
Every station has it's target demographics and they live and die by those numbers which eventually get exposed one way or another.