Except as provided in subsection (b) of this section, an employee's regular hourly rate of pay is computed for purposes of this subtitle by dividing the employee's total regular weekly pay by the total number of hours in the employee's normal workweek. The regular hourly rate of pay for an employee of a hospital or domiciliary care facility for the ill, aged, or disabled may be computed for purposes of this subtitle by dividing the employee's total regular 2-week pay by the total number of hours in the employee's normal 2-week work period.