(a) Charging contributing employers. (1) Section 3303(a)(1) of the Internal Revenue Code of 1986 (26 U.S.C. 3303(a)(1)) does not require that Extended Benefits paid to an individual be charged to the experience rating accounts of employers.

(2) A State law may, however, consistently with section 3303(a)(1), require the charging of Extended Benefits paid to an individual; and if it does, it may provide for charging all or any portion of such compensation paid.

(3) Sharable regular compensation must be charged as all other regular compensation is charged under the State law.

(b) Payments by reimbursing employers. If an employer is reimbursing the State unemployment fund in lieu of paying contributions pursuant to the requirements of State law conforming with sections 3304(a)(6)(B) and 3309(a)(2) of the Internal Revenue Code of 1986 (26 U.S.C. 3304(a)(6)(B) and 3309(a)(2)), the State law shall require the employer to reimburse the State unemployment fund for not less than 50 percent of any sharable compensation that is attributable under the State law to service with such employer; and as to any compensation which is not sharable compensation under § 615.14, the State law shall require the employer to reimburse the State unemployment fund for 100 percent, instead of 50 percent, of any such compensation paid.