Shift workers working straight time on Sunday shall be paid an additional thirty-five cents ($.35) per hour. Effective January 1, 1988, shift workers working straight time on Saturday shall be paid an additional thirty-five cents ($.35) per hour and shift workers working straight time on Sunday shall have their Sunday shift pay increased to sixty cents ($.60) per hour. Shift workers working Christmas Eve and New Year's Eve shall be paid twelve (12) hours at their regular straight time rate. Shift workers working the six major holidays shall be paid ten (10) hours at their regular straight time rate.