Wrong bill of quantities, rejected bid: why a forgotten tab costs the NMBS contractor the ‘CW Mechelen’ contract
The Council of State rejects the extreme-urgency action of a contractor who lost out on the NMBS works ‘CW Mechelen – modification of the transhipment bed’: by mistakenly using an outdated bill of quantities it left the entire ‘6.3 Work stoppage’ tab blank, and that is not a ‘purely material error’ the authority had to correct but a substantial irregularity that makes price comparison impossible — all the more so as price was the sole award criterion.
What happened?
The NMBS placed, in the special sectors, a works contract for ‘CW Mechelen – modification of the transhipment bed and surroundings’, through a simplified negotiated procedure with prior call for competition and with price as the sole award criterion. After two notices of amendment the submission deadline was moved to 23 January 2026. Four bidders submitted an initial offer. Following an initial analysis, on 30 January 2026 the authority invited all four bidders to submit a revised offer, together with a new model bill of quantities containing an additional ‘6.3 Work stoppage’ tab — intended to capture the costs of a full work stoppage (idle labour, immobilised vehicle or machine) in separate items. The applicant submitted its revised, final offer on 13 February 2026 but mistakenly attached an older version of the bill of quantities without that tab, so that no unit prices were given for the new items. On 16 February 2026 it reported the mistake by e-mail and asked to correct it; on 11 March 2026 it repeated this by registered letter, pointing among other things to the gap-filling formula of article 84(2) of the Royal Decree of 18 June 2017 and to its unit prices ‘under the concrete contract’. On 25 March 2026 the NMBS awarded the contract to another bidder and declared the applicant's revised offer substantially irregular: the absence of price data for the new items prevented assessment of the offer and made comparison with the other offers impossible, while completing it would amount to a new offer. The applicant turned to the Council of State under extreme urgency. In a first ground with four limbs it argued that this was a ‘purely material error’ within the meaning of article 42 that the authority had to correct, that the gap-filling formula of article 84(2) had to be applied at least by analogy, that there was no substantial irregularity or that the offer could be regularised (article 74), and that adding a whole tab of 21 items was a substantial modification requiring a fresh tender. The Council followed none of these. An offer that is incomplete through carelessness is not in itself a ‘purely material error’: it is first and foremost for the bidder to draft and submit its offer carefully and completely, and the applicant had two weeks (30 January to 13 February) to use the amended bill of quantities. The unit prices from the ‘concrete contract’ could not be transposed one-to-one — that contract did not contain all the items of the ‘General’ tab — and the applicant moreover used a contradictory ‘clustering technique’, by which it claimed already to have spread the stoppage costs over the other items. Price is an essential element of the offer, all the more as it was the sole award criterion, so the missing items did affect price formation and comparability. The gap-filling formula of article 84(2) did not apply: that provision sits under the heading ‘Award by open or restricted procedure’ and thus does not cover a negotiated procedure, and the legislative history reveals no gap justifying analogous application. The authority was entitled to treat the irregularity as substantial and to find that regularisation here would amount to submitting a new offer, contrary to equal treatment. The binary reasoning — either non-substantial and thus correctable, or substantial and thus requiring re-tendering — ignores the autonomous doctrine of the substantial modification, which is distinct from articles 42 and 74. In a second ground the applicant accused the NMBS of not having conducted a proper price and cost investigation, but the Council confirmed that the general price investigation (article 43) is always mandatory, whereas the special price investigation with a price query (article 44) is required only where there are indications of abnormal prices and may be carried out on the last submitted offer. Neither ground was serious; the application for suspension was rejected.
Why does this matter?
This arrest sharpens the bidder's duty of care and delimits three frequently confused legal concepts. First: an offer that is incomplete because you yourself used the wrong bill of quantities is not a ‘purely material error’ within the meaning of article 42 of the Royal Decree of 18 June 2017. That concept is narrow — it targets slips about which there can be hardly any discussion — and neither the absence of a speculative intent nor the limited size of the error changes this. Second: the gap-filling formula by which an authority can mathematically supply a missing unit price (article 84(2)) applies only to the open and restricted procedure, not to negotiated procedures; you cannot enforce it ‘by analogy’. Third: even where regularisation is possible (article 74(5)), it is not absolute — it may not amount to your effectively submitting a new offer, because that breaches equal treatment of bidders. For authorities, the arrest confirms that they may reject an offer that does not respect the prescribed manner of stating prices where this prevents comparison with the other offers, certainly where price is the sole award criterion. And it repeats the two-step system of the price investigation: the general investigation (article 43) is always mandatory, the special one (article 44) only upon indications, if need be on the final offer.
The lesson
Treat the bill of quantities as a document on which your entire offer stands or falls: always use the most recent version and check, item by item, that every mandatory tab is filled in before you submit. If you are counting on a later correction, bear in mind that a mistake through carelessness is not a ‘purely material error’ the authority must correct, that the gap-filling formula of article 84(2) does not apply in a negotiated procedure, and that a regularisation amounting to a new offer is prohibited in any event. Referring to unit prices ‘from another contract’ only helps if those prices fit the items at hand one-to-one and without assumptions — and it is for you to show this concretely, not for the Council to work it out for you. Finally, avoid contradictory defences (the items are ‘negligible’ and ‘already accounted for in the other items’): such inconsistency undermines the seriousness of your case.
Ask yourself
Suppose you have just noticed that you used an outdated bill of quantities for your submitted offer and left a whole tab blank. Can you, regardless of your good faith, show that this is a slip about which there can be hardly any discussion and that can be put right without any assumption? Did you actually place the invitation to submit a revised offer and the new model bill of quantities side by side with your submission before you filed it? If you rely on prices from another contract, can you point to a corresponding price for every missing item — or does it remain a general reference? And do you keep your defence consistent, or do you say at the same time that the items are negligible and that you have already accounted for them elsewhere?
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 →