(1) Each natural gas utility petitioning for interim rate relief pursuant to Florida Statutes § 366.071, shall file the data required in Fl. Admin. Code R. 25-7.039(1)(a)
    (2)(a) Interim rates shall apply across the board based on base rate revenues for the test period less base gas revenue by rate schedule. The resulting dollar amount shall be divided by base rate revenues per rate schedule to determine the percent increase applied to each rate schedule.
    (b) In determining the interim increase, the following data shall be provided by rate schedule: Therm sales; base rate revenue less base gas cost; base gas revenue; total base rate revenue; purchased gas adjustment revenue; total revenue. The interim increase shall be shown by dollar amount and percentage by rate schedule calculated in the following manner: