The Secretary of State may by order—
vary the provisions of sections 8 and 9 as to the particulars which must be included in a pay statement or a standing statement of fixed deductions by adding items to, or removing items from, the particulars listed in those sections or by amending any such particulars, and
vary the provisions of subsections (4) and (5) of section 9 so as to shorten or extend the periods of twelve months referred to in those subsections, or those periods as varied from time to time under this section.