A use, (other than a residential unit development), subject to a conditional use permit; shall place new on-site utilities underground, and shall place existing, on-site utility lines underground, or pay a fee in-lieu thereof, according to the following formula:
The number of feet of existing overhead lines to be placed underground shall be the square root of the "assumed lot size."
The "assumed lot size" shall be the gross floor area of the new construction multiplied by four.
If the amount of line to be placed underground is less than 300 feet, the in-lieu fee described in Section 16.151.010.D shall be paid. If the amount of line is 300 feet or more, the property owner shall underground that number of feet of existing utility lines, or to the first point of connection, whichever is shorter.