(a) The fee or charge imposed by any telephone company doing business in this state for the initiation of local telephone service at a residential location, but not including contributions in aid of construction, if any, shall be billed to the residential customer in equal monthly installments over a period of six (6) months at the option of the customer if the total installation charges exceed one hundred dollars ($100).
(b) If the total installation charges exceed fifty dollars ($50.00) but do not exceed one hundred dollars ($100), the residential customer shall at the option of the customer be billed in equal monthly installments over a period of three (3) months.