Section 18. Night-Shift Differential. —

1. Every public health worker shall be paid a night-shift differential of ten percent (10%) of his/her regular wage for each hour of work performed during the night-shifts customarily adopted by hospitals.

2. Every health worker required to work on the period covered after his/her regular schedule shall be entitled to his/her regular wage plus the regular overtime rate and an additional amount of ten percent (10%) of such overtime rate for each hour of work performed between ten (10) o'clock in the evening to six (6) o'clock in the morning.