Unilaterally redrawing the price structure of an offer and calling it 'arithmetic-error correction' doesn't work — article 34 only covers errors whose result is contrary to the bidder's intention
The Council of State suspends the award of Charleroi's contract for rental and maintenance of work clothing because the city unilaterally 'corrected' CWS Workwear's prices under article 34 of the Procurement Royal Decree — while the alleged 'error' did not produce a result contrary to the bidder's intention, and the city did not seek the bidder's real intention but applied its own conception of what was acceptable.
What happened?
Charleroi launched an open procedure (CSC 2022-33) for the rental and maintenance of work clothing for its services — 7 lots with sub-lots (jackets, trousers, antistatic and flame-retardant clothing, high-visibility clothing, kitchen wear, rain protection). Duration 72 months (24 setup + 48 rental). Estimated value €606,598.13 excl. VAT. Three bidders: CWS Workwear België (€824,543.90), Mewa (€934,607.70), Depairon (€2,242,462.40). The inventory required 'unit prices excl. VAT' for the rental items, with stated quantities. On 18 July 2022, Charleroi wrote to CWS that its prices were given weekly and had to be converted to monthly by multiplying by 4.3333 (52 weeks / 12 months), 'under article 34 — correction of arithmetic errors'. Charleroi unilaterally applied this formula to all prices AND to the totals. On 22 July, CWS replied that its weekly unit prices times 4.3333 indeed gave the correct monthly unit prices — but on 25 July, it emailed that the conversion to the totals was not so simple, because its calculation divided the presumed quantity by the number of weeks, not multiplied. On 21 February 2023, Charleroi awarded the contract to Depairon (€2,242,462.40). In the evaluation, CWS's total had been artificially inflated, causing the actual lowest bidder to lose. CWS sought extreme-urgency suspension. The Council ruled sharply: article 34 requires the authority to seek the bidder's real intention by analysing the offer as a whole and comparing it with other offers and market prices. A 'purely material error' in article 34's sense is only an error whose result manifestly contradicts the bidder's intention. The exchange shows the opposite here: CWS accepted the unit-price conversion but not the resulting redrawing of the totals; Mewa had similar confusion. What contradicts the bidder's intention is in fact the correction. Charleroi did not rectify 'according to its own findings' after a subordinate clarification (as article 34 §2 paragraph 4 allows), but according to its own conception of what was acceptable. Since the rectification power is an exception to the principle of post-opening immutability, it must be strictly interpreted. Breach of article 34 appears prima facie established. Suspension granted.
Why does this matter?
Unit-price and quantity structures in inventories regularly produce ambiguities — especially in multi-year rental or maintenance contracts where the base period (week, month, year) is not unambiguously stated. The temptation to 'solve' such ambiguity unilaterally via article 34 is real. This ruling sets the legal brake: article 34 is not a tool to 'normalise' an unclear offer afterwards. It is an exception to the principle of immutability of an offer after opening — and exceptions are strictly construed. A 'material error' under article 34 means: an error whose effect the bidder evidently did not want. When a correction fundamentally changes the bid (multiplying totals by 4.3333 without the bidder's agreement), it is no longer a rectification but a revision — and that is forbidden.
The lesson
As an authority, when after opening you receive an offer with a price structure that doesn't match your inventory, the right reflex is not 'we'll just recalculate mathematically and announce it as article-34 rectification'. The right reflex is to ask the bidder for their real intention, and if that is unclear or unacceptable, decide either that the unit prices apply or reject the offer as irregular. Unilateral arithmetic redrawing according to your own conception of 'logical' produces a suspendable decision. As a bidder receiving an article-34 'rectification', respond crystal-clear and componentwise — what you accept (e.g. unit-price correction) and what you explicitly do not accept (e.g. derivation to totals).
Ask yourself
If your authority sends a mail 'under article 34 we correct the following errors…' and the rectification changes your total: have you confirmed or refused each component explicitly and separately? A general 'agreement' on the unit-price correction will otherwise be construed against you as agreement to all derived recalculations.
About this database
The Council of State (Raad van State / Conseil d'État) is Belgium's supreme administrative court. In disputes over public procurement — from contract awards to tenderer exclusions — the Council of State is the final arbiter. The rulings in this database are summarised by TenderWolf in plain language, with practical lessons for tenderers and contracting authorities. View all rulings →