Need another set of eyes to look at this 1 please?

http://www.excelforum.com/excel-form...f-formula.html

The formula works perfectly, except for a handful of names. I am using OFFSET(*) to get the month column - when I use that, a few names throw an error, when I use the actual column ref, it works. The OFFSET() does not use a name, so that cant be it - I have tested all the data in the column, it is all numbers. Cant find the problem