The principles discussed in Sec. Sec. 778.220 and 778.221 are also applied with respect to certain types of extra payments which are similar to call-back pay, such as: (a) Extra payments made to employees, on infrequent and sporadic occasions, for failure to give the employee sufficient notice to report for work on regular days of rest or during hours outside of his regular work schedule; and (b) extra payments made, on infrequent and sporadic occasions, solely because the employee has been called back to work before the expiration of a specified number of hours between shifts or tours of duty, sometimes referred to as a ``rest period.'' The extra payment, over and above the employee's earnings for the hours actually worked at his applicable rate (straight time or overtime, as the case may be), is considered as a payment that is not made for hours worked.