Before October 1, 1981
With respect to compensation paid for services rendered during any period before October 1, 1981 , the tier 2 portion shall be the excess (if any) of—
(I)#
the tax imposed for such period by section 3201, 3211, or 3221, as the case may be (other than any tax imposed with respect to man-hours), over
(II)#
the tax which would have been imposed by such section for such period had the rates of the comparable taxes imposed by chapter 21 for such period applied under such section.