(1) When because of differences in minimum weights, package requirements, mixed truckload provisions, or other conditions the charges accruing under commodity rates result in higher charges than those accruing under the class rates published in other tariffs, provision may be made in a tariff containing commodity rates only, for the alternation of such rates with class rates published in not more than three other tariffs containing class rates only, provided that the commodity tariff contains specific reference to the PSC number or numbers of the class tariffs and shows in connection with each PSC number a complete description of the origin and destination territory shown in that tariff. The following notation must be shown in the commodity tariff under the application of rates:

(a) If the charges accruing under the class rates published in the following tariffs, including supplements to or successive issues thereof, from and to the same points via the same routes are lower than the charges accruing under the commodity rates published in this tariff, the lower charges resulting from such class rates will apply. (Here show PSC numbers of the class tariffs and the required description of each.)

(2) If a commodity tariff contains only a few rates which result in higher charges than would accrue under the class rates the reference to the class tariffs prescribed herein should be shown immediately in connection with such commodity rates or may be shown in a separate item under an appropriate heading and reference to such item shown immediately in connection with the commodity rates.

(3) Great care should be exercised in describing the scope of the class tariffs in order that users of the commodity tariff may determine without examining the class tariffs, which of such class tariffs is to be used in connection with any commodity rate. It also should be understood that the alternative application of commodity rates in one tariff with class rates in another tariff should be resorted to only where there is real necessity therefore and that wherever possible the commodity rates should be revised so that they will not exceed the class rates between the same points.

(4) The continuance of the authority contained in this section will depend upon the progress made by carriers in revising commodity rates in order to avoid unnecessary alternations, and upon the accuracy used in describing the class.