At issue: Whether the determination of the fees, upon which the charges to it were based, was invalid. As an interlocutory measure it has sought extensive discovery going to the costs of supplying electricity in the Territory. The question whether such discovery should be ordered depends ultimately upon the construction of the Ordinance. In particular it depends upon whether it is necessary in deciding upon the validity of the determination, to know what were the actual costs of supply to the relevant users in the period for which charges based upon that determination were raised.