Refunding bonds shall not be issued if the total interest cost to maturity on the refunding bonds plus the principal amount of the refunding bonds exceeds the total interest cost to maturity on the bonds to be refunded plus the principal amount of the bonds to be refunded. Subject to these limitations, the principal amount of the refunding bonds may be more than, less than, or the same as the principal amount of the bonds to be refunded.
Ca. Gov. Code § 53362.5