Interest on net cash tax liability now payable only on amounts debited to electronic cash ledger, with retrospective effect. The amendment replaces the proviso to the interest provision to state that interest on tax declared in a return furnished after the due date is payable only on the portion of tax paid by debiting the electronic cash ledger, except where the return is filed after commencement of assessment proceedings; the substitution is given retrospective effect, changing the computation basis to the net cash component.