the employees of an interstate Compact agency operating in the national capital area may not consider the wages, benefits, and terms and conditions of employment of employees working outside of the District of Columbia, Maryland, and Virginia. (5) The wages, benefits, and terms and conditions of employment applicable to other employees of the interstate Compact agency taking into account the special nature of the work performed by the employees in the bargaining unit, including any hazards or the relative ease of employment, physical requirements, educational qualifications, job training and skills, shift assignments, and the demands placed upon the employees as compared to only other employees of the same interstate Compact agency. (6) The interests and welfare of the employees in the bargaining unit, including— (A) the overall compensation presently received by the employees, having regard not only for wage rates but also for wages for time not worked, including vacations, holidays, and other excused absences