Start with the first difference, not the grand total
If a BC3 estimate opens successfully but its total changes, adding an adjustment item may hide the cause. Compare one work item first and follow its resources, quantities, prices and amounts. This guide focuses on calculation differences; if chapters or text are missing, start by reviewing the complete import. Not every small discrepancy comes from rounding.
Distinguish displayed decimals from calculation precision
A screen may display two decimal places while retaining greater precision for calculations. Record which value is exported, imported and used in each operation. The FIEBDC-3/2024 specification defines decimal conventions in the ~K record. Consult the rules for each magnitude; do not apply one precision to prices, resource consumption, dimensions and sums.
Fictional example: rounding earlier changes the answer
As an arithmetic demonstration, 3 units multiplied by 1.234 euros give 3.702 euros, rounded to two decimals as 3.70. Rounding the price to 1.23 first and then multiplying gives 3.69. The one-cent difference does not establish the file’s correct result: that depends on the applicable convention. This example does not specify how every application calculates.
Prepare a minimal reproducible sample
Keep the original and work with a copy containing an affected item and its dependencies. Record the source application and version, declared format version, destination application and import settings. Compare quantity, price, resource consumption, direct cost, percentages and total on both sides. Where several currencies or price scopes exist, also check that you are comparing the same selection.
Do not confuse rounding with commercial changes
A difference may result from discounts, indirect costs, omitted concepts or different units. Separate these causes before defining a tolerance. A tolerance helps decide what to review; it does not make a discrepancy correct. Document where the difference appears and the rule accepted by the team. Avoid correcting the total without explaining its underlying calculations.
Agree the result before connecting the ERP
Define which amounts must be preserved and which the destination may recalculate, using a comparison approved by the estimate owner. Check the return export too and retain the differences report. CADT can review an anonymised sample and help establish import and reconciliation rules. The ERP then receives an explainable baseline rather than an apparently balanced total without traceability.