If an employer chooses a per diem method of substantiation for travel expenses, a. The Regular Federal Rate method allows employees the same per diem rate no matter where they travel in the United States. b. Actual expense records substantiating the business reason for the trip and the dates of arrival and departure are not required. c. The meals and incidental expenses method requires actual cost records to substantiate lodging expenses. d. The employer need not use an accountable plan for reimbursing employees for travel expenses. e. The high-low method averages the high-cost locality and low-cost locality per diem rates to arrive at an average rate