Exception for B2B-only transactions where nearly all receipts are non-cash, relieving them from cash-expense disallowance rules. The provision does not apply to persons engaged exclusively in B2B transactions provided a qualifying compliance threshold is met: a substantial majority of aggregate receipts for the previous year, including sales, turnover or gross receipts, are received by modes other than cash, creating an exclusion from the cash-expense disallowance mechanism for such entities.