A charge may not be made by the utility for the underground installation, except in accordance with tariffs filed with the Commission and the following general guidelines:
A. The service connection to the building normally will be at the corner of the building nearest the point at which the underground electric service line enters the property to be served.
B. Each applicant will cooperate with the utility in an effort to keep the cost of construction and installation of the underground electric distribution system or service line as low as possible. Additional costs arising from failure of the applicant to cooperate with the utility, such as his making changes in grade or failing to maintain grade, shall be borne by the applicant.
C. If an underground installation is to be constructed within a subdivision designed to include large open areas which would result in an abnormal increase in the investment per customer required to construct the underground distribution system, then the utility may refer the matter to the Commission for a ruling as to whether a charge should be assessed against the applicant, and the amount of the charge, if any.