If look back is enabled, rating will initially compute the charge amount for the tariff charge using the rate for the applicable range break. Rating will also compute the charge amount using the rate for the previous range, applying the maximum number of units at the previous range. The higher of the two amounts will be used. If the look-back rate is used, the Rated As Units for the charge will be the high end of the pervious range break.
For example: Assume a Range Code has range breaks at 1-100, 101-200 and 201-300 pounds. Assume the rates are $.50, $0.40 and $0.30 per pound for each of these ranges. If the weight for a shipment is 210 pounds, rating will initially compute the amount as $63.00 (210 pounds * $0.30). Look-back will then compute the amount at the high end of the previous range break as $80.00 (200 pounds * $0.40). In this case, the look-back amount will be used. If the weight was 280 pounds, the rate corresponding to the actual weight would be used, as $84.00 (280 * $0.30) is greater than $80.00 (200 * $0.40).
Look back will not be considered when the look-up units correspond to the lowest range break.
Note: If neither Look Ahead or Look Back are enabled for a tariff charge (and clipping is not enabled), the charge amount will be computed using the rate for the range break corresponding to the actual number of look-up units.
Note: Look-ahead and look-back should not be used in conjunction with clipping.