In the absence of regulations of the Franchise Tax Board and unless otherwise specifically provided, in cases where the Personal Income Tax Law or the Corporation Tax Law conform to the Internal Revenue Code, regulations under the Internal Revenue Code shall, insofar as possible, govern the interpretation of conforming state statutes, with due account for state terminology, state effective dates, and other obvious differences between state and federal law pertaining to, but not limited to, such matters as tax rates, taxable years, jurisdiction, and cross-references to other related statutes and regulations.