Creating Shipping Discount With Dependencies

I ship primarily via USPS domestic and international using Live Rates

USPS rates just went up, and when I ship via I get a discount. I would like to pass that discount on to the customer on checkout to offset the rate increase.

However, when I use Shipping Methods> Edit any shipping method (Priority Mail for example) > Shipping Charges tab it appears as though the Percentage option is calculated on the dollar amount of the merchandise (the sub-total) and NOT the shipping charges.


Add one item to the cart valued at $4. Priority Mail cost is $6.

Create a Cost Dependency: Product cost more than $0, rate value = -10, type = Percent (%).

The shipping cost now calculates at $5.60 in the cart ($4 item cost - 10% = $.4)

The shipping cost SHOULD calculate at $5.40 in the cart ($6 shipping cost - 10% = $.6)

If I add an $8 items to the cart (sub-total = $8 the 10% discount on shipping is $.80

It appears as though the logic in Shipping Charges is calculated on the sub-total and NOT the cost of shipping - which is a real problem for anyone that intends to use Percentages!

The same results are realized with Weight Dependency, so I don't think it's exclusive to Cost Dependency.

Anyone else try this EVER? Any solution? Is it just impossible to use NEGATIVE values with percentages, or to calculate ON the Shipping Charges when using ACTUAL Live Rates? or is CS-Cart just lazy? Basically, I assumed that the Shipping Charges tab allowed me to tweak shipping charges - but it really only modifies the charges based upon the sub-total and doesn't REALLY calculate ON the shipping charges. Which makes it nothing more than a place to add a few dollars to the cost of the order and hide it in the shipping charges. Duh.

The Reference Guide does NOT mention the use of negative values (even though negative values can be added to the rate value field).

Hi Magpie Don,

I am trying to also use live rates, but for DHL. I want to discount the rates that are generated by a percentage using the weight modifier, but cannot get a negative percentage to work. The software only sub tracks the actual amount, but won't subtract a percentage, even though we have selected the percentage TYPE of rate modifier. (Currently the calculations work as follow: $150 live shipping rate - 30% = $120.00 As a percentage it should equal $105.00.) Good news is that it seems to be subtracting from the DHL rate, but won't figure a percentage and subtract that amount. Only a fixed dollar amount.

Did you have any success in finding an answer to your questions above?


CS-Cart v 4.3.5