A licensee shall, upon the consummation of a sale of a hearing aid, keep and maintain records in the licensee’s office or place of business at all times and each record shall be kept and maintained for a seven-year period. All records related to the sale and fitting of hearing aids shall be open to inspection by the board or its authorized representatives upon reasonable notice. The records kept shall include:

1. (a) Results of test techniques as they pertain to fitting of the hearing aid.
2. (b) A copy of the written notice and the written receipt required by Section 2538.35 and the written recommendation and receipt required by Section 2538.36 when applicable.
3. (c) Records of maintenance or calibration of equipment used in the practice of fitting or selling hearing aids.