Also, there are some errors in the grid. For example, the misplaced the old calls WCAA where WXNY's current numbers are.
The October survey ended on the 15th, and the WXNY calls went into effect on 10/16.
That's also a bit surprising as I thought there wouldn't be a drop-off of more than half because of the frequency shift. I have to think that's an error as well.
No, there is no error, because Arbitron considers a frequency change with either a name or call change and a format change to be a new station. WCAA 96.3 only had numbers in the last week of the book. The monthly number, though, is an average of 4 weeks. So three weeks at 0 and one at 3.6 gets a month at 0.9.