WHY ARE ODP AGE DIVISIONS DIFFERENT FROM CLUBS?

ODP uses pure calendar years to determine age groups.  The ODP is a feeder system into the National Youth Teams.  Hence, it has to be in line with the international age classification.  National Teams must abide with FIFA's (the international governing body for soccer) age classification, which follows the calendar year.  An ODP age group therefore goes from January 1st to December 31st, while the American youth clubs use August 1st to July 31st.