A mixed cart adds several shipping-class charges

Identify the Flat Rate instance behind the amount

Start with the real cart or order that prompted the question. Record its products or variations, quantities, selected shipping method and the settings that supplied that method. The comparison here applies to WooCommerce's documented Flat Rate method. A carrier rate or an extension with a similar display name needs its own explanation.

Keep the shipping amount separate from the merchandise total and any shipping tax. Flat Rate's tax status controls whether tax applies to its cost. Comparing a tax-inclusive display with only a class-cost field can make a correct calculation look unexplained. Record the components as shown; this worksheet does not determine the tax the business owes.

Compare the two class calculations with the same inputs

Under per-class calculation, add the applicable cost for each distinct shipping class present, then add the method's base cost. Under per-order calculation, select the highest applicable class cost, then add the same base cost. Per order does not mean that the base cost disappears, and per class does not mean that every product line automatically adds another copy of a fixed class charge.

For fixed amounts, this gives two useful comparisons: base plus the sum of applicable class amounts, and base plus the largest applicable class amount. Use only the values in your own settings. If a cost field contains a calculation rather than a fixed amount, preserve the expression and obtain its result for the actual cart before comparing modes. Do not treat the expression's text as a money amount or invent a result.

With only one contributing class, the two modes can produce the same class contribution. That observation cannot distinguish the modes. A real mixed cart with several contributing classes is the relevant record, and the saved calculation mode remains the direct evidence of the configured choice.

Decide whether the mode or the underlying assignment conflicts with policy

Read the business's actual rate policy alongside the two calculations. A policy that charges for each class represented points toward a different configuration from a policy that uses only the highest class amount for the order. The lower result is not automatically the correct result; the intended rule must come from the merchant.

Inspect the class assignment before changing the mode. If a real product has the wrong class, changing the mode can hide that mistake while changing charges for other mixed carts. Likewise, a wrong base cost or class amount is a different discrepancy from the choice between sum and highest. Name the field that conflicts with the approved rule.

If neither reconstructed amount matches the observed shipping line, the mode alone has not explained it. Preserve the difference, the cost expressions, tax treatment and rate-producing component for the maintainer. Do not keep changing class prices until one unexplained total happens to look right.

Authorize a specific correction and keep its basis

The decision record should identify the current mode, the intended rule, the exact setting or product assignment to change and the owner authorized to change it. Keep the earlier settings and the real observation together so a later reviewer can tell whether the change corrected policy or merely reduced a charge. After authorized work, compare the affected shipping behavior with that stated rule using real records.

For a Prism checkout consultation, describe the platform, mixed-cart behavior and mismatch between the published shipping terms and saved settings. Request the help you need; scope, responsibilities, fees and terms are confirmed before work begins. The consultation does not itself change shipping settings or establish payment-provider eligibility.

Shipping-class calculation check

Complete this for one real mixed cart and its selected Flat Rate instance. Calculate both modes from the same recorded inputs. A match explains the amount only to the extent those inputs and the rate source are confirmed; choose a correction from the approved policy, not from which total is lower.

Worksheet entries are not submitted by Prism’s worksheet and are not saved by the site. Use record types, availability, anonymized observations, or match/mismatch results. Do not enter government identifiers, customer names or addresses, customer messages, receipt-access links, card or bank details, passwords, or keys. Send sensitive documents only through the provider’s verified secure channel.

These are temporary notes. Leaving or reloading this page may clear them. Worksheet entries are not sent automatically. If you copy notes into the consultation message and submit the form, Prism receives them as part of your request.