How to compare two revisions of a BC3 estimate

Before importing a revision, retain both original files and a summary produced by each application. Record project, date, author, estimate version and scope. Compare the same currency and the same approach to including additional costs. A file received later is not necessarily the approved estimate. Identify who may accept changes and keep the incoming revision pending until the checks are complete.

Prepare a table containing chapter, code, unit, description, quantity, price and amount for each item. Use the stable relationship supported by your system and review codes repeated under different chapters. Do not compare row 25 in one file with row 25 in the other: an inserted item shifts subsequent rows. If a code has changed, document the mapping; matching descriptions alone do not prove that two items represent the same work.

Classify each difference: new item, missing item, quantity change, price change, description change or relocation. A missing item may result from a partial export rather than an approved deletion. Changes of unit require review before quantities can be compared. Record differences even when the overall total agrees: an increase in one chapter may be offset by a reduction elsewhere, concealing a change in scope.

Fictional example without additional charges: an item changes from 100 m² at €20/m² to 120 m² at €22/m². Its amount increases from €2,000 to €2,640. One consistent way to explain the €640 difference is €400 for the quantity increase at the old price and €240 for the price increase applied to the new quantity. Apply the same method throughout the report and document rounding.

FIEBDC publishes the format definition and resources for checking BC3 files. Technical exchange checks and approval of a change serve different purposes: opening a file does not establish that its changes are authorised. Check in the applications that measurement lines and required information survive. Then link every accepted difference to its reason, owner and date. Keep unresolved observations visible instead of treating import success as approval.

Run the update on a test copy first. Check affected items, chapter totals and links to existing purchases or progress valuations. Do not overwrite historical amounts merely to match the new estimate. Retain a difference report and the accepted revision. CADT can help define the transfer from BC3 to ERP so that revisions update outstanding work while preserving the history of the project.