Withholding tax on commissions limited by amendment, restricting applicability to a specified prior period for payments. The provision inserts the words 'but before the 1st day of June, 1992' into the specified subsection after the existing reference to the earlier commencement date, with that insertion to have effect from the 1st day of June, 1992, thereby limiting the temporal applicability of the withholding obligation for commission and brokerage payments under the subsection.