lated sick leave at 50% of full pay remaining unused at the time of retirement or death shall be compensated to the employee or, in the event of the death of the employee, to the employee’s legal beneficiaries by a cash payment of 50% of the employee's salary rate on the date of retirement or death. Commencing December 24, 2028, and thereafter, payouts of the balance of specified accumulated sick leave shall revert back to being compensated under the provision codified in the immediately preceding paragraph, which provides for cash payment of 50% or 25%, whichever is applicable, of the salary rate current at the date of payment. The appointing authority shall authorize cash payment to the legal beneficiaries of any City employee who is killed during the performance of job-related duties for the balance of the employee’s accumulated full-pay sick leave at 100% of the employee’s salary rate on the date of the employee’s death. In no instance shall an employee or the employee’s beneficiaries be compensated more than once for accumulated full pay sick leave and 50% sick leave upon retirement and/or death of the employee. The provisions of Subsection (b) herein that pertain to payments upon retirement or death are applicable only to employees who at the time of their retirement or death were employed in a City department other than the Department of Water and Power. (c) Any unused balance of sick leave at 75% of full pay at the end of any calendar year shall be carried over and accumulated from one calendar year to the next to a maximum of 800 hours at 75% pay. All accrued sick leave at partial pay in excess of such maximum amounts shall be deemed waived and lost. (d) Upon approval of the appointing authority, any employee may be allowed sick leave with full pay not to exceed an aggregate of 48 hours in any one calendar year but in not less than one-half hour increments at any one time, which shall be included in the allowance of sick leave at full pay under this section for the purpose of securing preventive medical, dental, optical or other like treatment or examination for the employee and for members of the employee’s immediate family or, effective January 1, 2023, the employee’s designated person as defined in Section 4.127 of this Code.