“Net income” means the total receipts allocated to income during an accounting period minus the disbursements made from income during the accounting period, plus or minus transfers under this chapter to or from income during the accounting period. During any period in which the trust is being administered as a unitrust, either pursuant to the powers conferred by Sections 16336.4 to 16336.6, inclusive, or pursuant to the terms of the governing instrument, “net income” means the unitrust amount, if the unitrust amount is no less than 3 percent and no more than 5 percent of the fair market value of the trust assets, whether determined annually or averaged on a multiple year basis.