(a) Subject to subdivision (b), this part applies in any case where authority to administer the estate is granted under this part or where independent administration authority was granted under prior law.
(b) If the personal representative was granted independent administration authority prior to July 1, 1988, the personal representative may use that existing authority on and after July 1, 1988, to borrow money on a loan secured by an encumbrance upon real property, whether or not that existing authority includes the authority to sell real property.