but did not pay tax by reason of asserting an intermediate and export sales exemption shall keep records sufficient to determine whether said exemption was valid for a period of 7 years after the purchase of taxable property or services. 509. Tax to be separately stated and charged (a) In General For each purchase of taxable property or services for which a tax is imposed by section 101, the seller shall charge the tax imposed by section 101 separately from the purchase. For purchase of taxable property or services for which a tax is imposed by section 101, the seller shall provide to the purchaser a receipt for each transaction that includes— (1) the property or services price exclusive of tax, (2) the amount of tax paid, (3) the property or service price inclusive of tax, (4) the tax rate (the amount of tax paid (per paragraph (2)) divided by the property or service price inclusive of tax (per paragraph (3)), (5) the date that the good or service was sold, (6) the name of the vendor, and (7) the vendor registration number. (b) Vending Machine Exception The requirements of subsection (a) shall be inapplicable in the case of sales by vending machines. Vending machines for purposes of this subsection are machines— (1) that dispense taxable property in exchange for coins or currency, and (2) that sell no single item exceeding $10 per unit in price. (c) Financial Intermediation Services Exception The requirements of subsection (a) shall be inapplicable in the case of sales financial intermediation service. Receipts shall be issued when the tax is imposed (in accordance with section 803 (relating to timing of tax on financial intermediation services)). 510. Coordination with title 11 No addition to tax shall be made under section 504 with respect to a period during which a case is pending under title 11, United States Code— (1) if such tax was incurred by the estate and the failure occurred pursuant to an order of the court finding probable insufficiency of funds of the estate to pay administrative expenses, or (2)