Either fix the code for OOP or split the OOP date:
1) Start the age 4 hours earlier than you want Jan 1st to start
2) Turn OOP into a 4 hour event. 25% of the server on each part. First group gets 1 hour to hit while all other parts are locked. 2nd group gets 1 hour to hit while all other parts are locked, etc. Then when all 4 are done, begin May 2nd. Simple. It will coincide with the correct date since we started protection 4 hours earlier.