The report shall be prepared on the accrual basis of accounting. Under the accrual basis of accounting, revenue is recorded in the period when it is earned, regardless of when it is collected, and expenses are recorded in the period when they are incurred, regardless of when they are paid. Particular attention shall be given to an accurate accrual of all costs at the close of the period for the equitable distribution of costs to the period applicable. Significant costs to be considered shall include, but not be limited to, employe payrolls, bonuses, and professional fees. Care shall be given to the proper allocation of costs for service and maintenance contracts to the period covered by such contracts.
61 Pa. Code § 521.3