(B) one-eighty-fourth of the gross payments for tangible personal property for 84 months or until the property is sold, (C) one-sixtieth of the gross payments for vehicles for 60 months or until the property is sold, or (D) for other types of taxable property or services, a reasonable amount or in accordance with regulations prescribed by the Secretary. (5) Business use ratio For purposes of this section, the term business use ratio means the ratio of business use to total use for a particular calendar month (or portion thereof if the property was owned for only part of said calendar month). For vehicles, the business use ratio will be the ratio of business purpose miles to total miles in a particular calendar month. For real property, the business use ratio is the ratio of floor space used primarily for business purposes to total floor space in a particular calendar month. For tangible personal property (except for vehicles), the business use ratio is the ratio of total time used for business purposes to total time used in a particular calendar year. For other property or services, the business ratio shall be calculated using a reasonable method. Reasonable records must be maintained to support a person’s business use of the mixed use property or service. (b) Timing of Business Use Conversion Credit Arising Out of Ownership of Mixed Use Property A person entitled to a credit pursuant to subsection (a)(3) arising out of the ownership of mixed use property must account for the mixed use on a calendar year basis, and may file for the credit with respect to mixed use property in any month following the calendar year giving rise to the credit. (c) Cross Reference For business use conversion credit, see section 202. 706. Not-for-Profit organizations (a) Not-for-Profit Organizations Dues, contributions, and similar payments to qualified not-for-profit organizations shall not be considered gross payments for taxable property or services for purposes of this subtitle. (b) Definition For purposes of this section, the