Sec. 3. (a) A disclaimer of an interest in property by an appointee of a power of appointment takes effect as of the time the instrument by which the holder exercises the power becomes irrevocable.
(b) A disclaimer of an interest in property by:
(1) persons eligible to receive property upon exercise of the power of appointment; or
(2) a taker in default of an exercise of a power of appointment;
takes effect as of the time the instrument creating the power becomes irrevocable.