(a) The amount of benefits paid to a claimant for a benefit year shall be charged to the accounts of each of the claimant's employers during the claimant's base period. The chargebacks of an employer for a calendar quarter are the benefits paid to all of the employer's employees or former employees during that quarter.
(b) The chargeback of benefits of a claimant who has two or more employers during the claimant's base period is allocated among those employers according to the proportion of the total of the claimant's benefit wage credits paid during the base period by each employer.