If it shall appear to the commissioner that an allocation factor determined pursuant to section 6 does not properly reflect the activity, business, receipts, capital, entire net worth or entire net income of a taxpayer reasonably attributable to the State, he may adjust it by:
(a) excluding one or more of the factors therein;
(b) including one or more other factors, such as expenses, purchases, contract values (minus subcontract values);
(c) excluding one or more assets in computing entire net worth; or
(d) excluding one or more assets in computing an allocation percentage; or
(e) applying any other similar or different method calculated to effect a fair and proper allocation of the entire net income and the entire net worth reasonably attributable to the State.