The function point measure itself is derived in a number of stages. Using a standardized set of basic criteria, each of the business functions is a numeric index according to its type and complexity. These indices are totalled to give an initial measure of size which is then normalized by incorporating a number of factors relating to the software as a whole. The end result is a single number called the Function Point index which measures the size and complexity of the software product. "
I will try and blog on my exp with this methodology, if any one else has used this before would appreciate your feed back.