The use of Civil Air Patrol leave under this subtitle may not result in the loss of an employee benefit accrued before the first date of leave. An employee using leave under Title 13 of the Public Safety Article may not concurrently use leave granted under this subtitle. This subtitle does not affect the obligation of an employer to comply with a collective bargaining agreement or an employee benefit plan that provides greater leave rights to employees than the rights provided under this subtitle. The grant of leave under this subtitle may not be diminished by a collective bargaining agreement or an employee benefit plan entered into on or after January 1, 2010. This subtitle does not affect or diminish the contract rights or seniority status of an employee not entitled to Civil Air Patrol leave.