(a) A durable power of attorney for health care entered into before July 1, 2004, under this part shall be given effect and interpreted in accord with this part.
(b) A durable power of attorney for health care entered into on or after July 1, 2004, that evidences an intent that it is entered into under this part shall be given effect and interpreted in accord with this part.
(c) A durable power of attorney for health care entered into on or after July 1, 2004, that does not evidence an intent that it is entered into under this part may, if it complies with the Tennessee Health Care Decisions Act, compiled in title 68, chapter 11, part 18, be given effect as an advance directive under that act.