Upon the confirmation of the sale of any real property of the estate, or upon the authorization of the borrowing of money secured by a mortgage or deed of trust on real property of the estate, the guardian or conservator shall furnish an additional bond as is required by the court in order to make the sum of the bonds furnished by the guardian or conservator equal to the amount determined pursuant to Section 2320, taking into account the proceeds of the sale or mortgage or deed of trust, unless the court makes an express finding stating the reason why the bond should not be increased. If a bond or additional bond is required under this section, the order confirming the sale of real property of the estate or authorizing the borrowing of money secured by a mortgage or deed of trust on real property of the estate is not effective and the court shall not file the order until the additional bond is filed.