3010.23—Calculation of percentage change in rates.
(a)
The term rate cell as applied in the test for compliance with the annual limitation shall apply to each and every separate rate identified in any applicable notice of rate adjustment for rates of general applicability. Thus, seasonal or temporary rates, for example, shall be identified and treated as rate cells separate and distinct from the corresponding non-seasonal or permanent rates.
(b)
For each class of mail, the percentage change in rates is calculated in three steps. First, the volume of each rate cell in the class is multiplied by the planned rate for the respective cell and the resulting products are summed. Then, the same set of rate cell volumes are multiplied by the corresponding current rate for each cell and the resulting products are summed. Finally, the percentage change in rates is calculated by dividing the results of the first step by the results of the second step and subtracting 1 from the quotient. The result is expressed as a percentage.
(c)
The formula for calculating the percentage change in rates for a class described in paragraph (b) of this section is as follows:
Percentage change in rates =
Code of Federal Regulations
Where,
N = number of rate cells in the class
i = denotes a rate cell (i = 1, 2, ..., N)
Ri,n = planned rate of rate cell i
Ri,c = current rate of rate cell i
Vi = volume of rate cell i
(d)
The volumes for each rate cell shall be obtained from the most recent available 12 months of Postal Service billing determinants. The Postal Service shall make reasonable adjustments to the billing determinants to account for the effects of classification changes such as the introduction, deletion, or redefinition of rate cells. Whenever possible, adjustments shall be based on known mail characteristics. The Postal Service shall identify and explain all adjustments. All information and calculations relied upon to develop the adjustments shall be provided together with an explanation of why the adjustments are appropriate.