The specific notification procedures set forth in this amendatory and supplementary act shall apply to any hearing or investigatory function involving:
a. Any adjustment of public utility rates, tolls, fares or charges, or schedules thereof;
b. The proposed or actual discontinuance, curtailment or abandonment of any essential public utility service;
c. The fixing of standards for the measurement of a public utility product or service pursuant to subsection b. of R.S. 48:2-25; and
d. Public utility surcharge collections, pursuant to R.S. 48:2-29.4.