Getting picky in CAML - Good

I have code in Excel that uses XMLHTTP to call SharePoints web services. The code contains a CAML query where I had a field reference to a Choice field , , this column has been converted to a Text (Single line of text) column and the query didn´t return any items anymore when running against MOSS 2007 instead of Wss 2.0. Then I updated the field reference to and the query returned items again.