My balance for an employee shows decimal places. He joined in the middle of the year; will he get the full entitlement for his annual leave? My entitlement settings are based on years of service.

No he will not. Even if the annual leave is setup as based on yearly entitlement, all new employees’ annual leave will still be prorated in the system for their first working year.  Only in the next calendar year after the employee completed the first working year will the employee get the full entitlement for his annual leave.