For purposes of s. 71.26 (2) (a) 7. and 9., “rental expenses” means the gross amounts that would otherwise be deductible under the Internal Revenue Code, as modified under s. 71.26 (3), for the use of, or the right to use, real property and tangible personal property in connection with real property, including services furnished or rendered in connection with such property, regardless of how reported for financial accounting purposes and regardless of how computed.