For purposes of this part, the term “lookback period” shall refer to the 12-month period between July l and June 30 immediately preceding the taxable year for which the filing frequency is determined by reference to the lookback period. Persons who were, during the entirety of the lookback period, not required to be licensed under a specific chapter of Part III of this title, shall be deemed to have had no taxable gross receipts during the lookback period with regard to that chapter.