May quantities cut by design variation be listed as negative BOQ items: the contract BOQ itself never goes negative - increases and decreases fall to the "variation increase-and-decrease price" item at final account; under lump-sum (fixed-price) contracts BOQ defects do not adjust, only differences between as-built and contract drawings form priceable variations (GB/T 50500-2024)

Topic Positioning

When a design variation cuts quantities: may the BOQ carry a "negative line" (negative quantity / deduct item), and how do quantity changes price under fixed-price (lump-sum) contracts? The core is separating the "contract BOQ itself" from the "settlement adjustment items", and drawing the line between "variation" and "BOQ defect".

Core Conclusions

1. Two layers never mixed: the BOQ itself never negative; the adjustment item may be

• BOQ quantities compute on design-shown dimensions under the contracted national / sector measurement standards and are positive by nature; under lump-sum contracts the divisional BOQ quantities "need no re-measurement" (GB/T 50500-2024 clause 7.2.2). Rewriting cuts as negative quantities in the original BOQ alters the BOQ itself - not a standard adjustment route.
• Clause 10.3.2: the final account price items, in order: 1 contract BOQ total; 2 BOQ-defect adjustment; 3 provisional-sums adjustment; 4 provisional-price adjustment (materials; specialist works under GC contracts); 5 main contractor's attendance adjustment (GC); 6 dayworks adjustment; 7 cost-fluctuation adjustment; 8 law and policy adjustment; 9 variation increase-and-decrease price; 10 additional works price; 11 claims; 12 delay liquidated damages; 13 other.
• Item 9, "variation increase-and-decrease price", is where cuts land, entered negative; the "contract BOQ total" line stands as contracted. Cuts list at the adjustment layer, never inside the original BOQ quantities.

2. First draw the variation / BOQ-defect line (decisive under lump-sum)

• Clause 7.4.3 (lump-sum variation measurement): "variations of lump-sum works compare the employer-issued or confirmed variation instruction with the as-built drawings against the CONTRACT drawings; the differing divisional BOQ items are the variation items, measured per clause 7.4.1."
• Continued: "whether unit-rate or lump-sum, the differing divisional items from that comparison are the variation items, measured under the contracted standards and supplementary rules. Differences between the CONTRACT DRAWINGS and the CONTRACT BOQ are BOQ defects: unit-rate works correct them per the rules; LUMP-SUM works never adjust for BOQ defects."
• Clause 7.4.2 (unit-rate): "variations recompute the divisional items and quantities from the instruction and the as-built drawings, compared against the defect-corrected BOQ to fix the items and quantities changed."
• Clause 7.2.2, lump-sum BOQ quantities: "1 divisional BOQ items need no re-measurement, and the contract price never adjusts for BOQ defects; BOQ items priced at provisional quantities and variations follow item 2; 2 items priced at provisional quantities measure per clause 7.2.1 item 1; 3 variations measure per clause 7.4.3."
• Clause 8.2.3: "under lump-sum contracts the price and time never adjust for BOQ defects; provisional-quantity unit-priced items may adjust per clauses 7.2.1 and 8.2.1." Preliminaries likewise - barring provisional-quantity items, no defect adjustment; statutory work-safety provisions moved by such adjustments follow the stated formulae.
• In practice: under lump-sum, "the drawings unchanged, only the BOQ short or wrong" cannot be re-priced via negative lines; only "the drawings changed" (as-built versus contract) prices.

3. How variations price

• Clause 8.9.3 (lump-sum variation pricing): "where contract rates apply to variations per the contract, quantity changes price per clause 7.4.3 measured quantities under 8.9.1 and 8.9.2; where they do not, the parties negotiate all-in rates from the execution, the market, the priced BOQ rules and the tendered level."
• Clause 8.9.1 (items added or removed, or quantity change within 15% inclusive): confirm the changed quantities per sections 7.1, 7.2, 7.4 and price: 1 identical items under identical conditions - the contract rate; 2 like items under identical conditions, or identical under like conditions - the analogous rate converted; 3 different items under identical conditions, or identical under different - negotiated market-reasonable rates by the analogous rules and tendered level; 4 different under different - negotiated from comparable projects; 5 variations cutting or cancelling items that markedly change the conditions - negotiated from the execution, market, rate rules and tendered level.
• Clause 8.9.2 (quantity change over 15%, exclusive): "1 added items and quantities may, per 8.9.1 and weighing the labour and material procurement discounts of the increase, reasonably LOWER the contract and new rates before pricing; 2 reduced items and quantities may, per 8.9.1 and weighing the discounts lost, reasonably RAISE the contract and new rates before pricing." Cuts thus never deduct pro rata at the old rate - raise the rate for the discounts lost, then price.
• Clause 8.2.1 (unit-rate BOQ defects): re-measure all items on the contract drawings per 7.2.1 and adjust: item changes or quantity moves within 15% inclusive price per 8.9.1; over 15% exclusive per 8.9.2.
• Clause 8.9.8 (omitted work): "where the employer's variation cancels a contracted work not due to the contractor, and the contractor's costs or expected profit appear in no other paid or payable item or substitute work, the employer compensates the loss and reasonable expected profit."
• Choosing contract rate versus adjusted or newly built rate turns on: item description (material change, method change, effects on other items, other description changes) and construction conditions (foundations, height, member sizes as in steel, season, protection of finished areas, access limits, transport modes, plant use, attendance within main contractor's provisions such as package quantity changes, other condition changes).

Applicability Boundaries

• Unit-rate and lump-sum differ: unit-rate corrects defects per 8.2.1 and adjusts; lump-sum never adjusts for defects - only drawing differences (variations) price (7.2.2, 7.4.2, 7.4.3, 8.2.3).
• The 15% base is the quantity of the item IN THE CONTRACT BOQ, judged item by item - never per unit work or per contract total; within 15% inclusive takes 8.9.1, beyond 8.9.2.
• "Settlement item 9 may be negative" is a listing rule - it never licenses negative quantities in the BOQ itself.
• Provisional-quantity unit-priced items still measure per 7.2.1 and adjust per 8.2.1 / 8.2.3 under lump-sum.
• Edition: GB/T 50500-2024 (in force 2025-09-01, replacing GB 50500-2013); the 2013 mandatory-clause approach to tender-BOQ accuracy differs from the 2024 contract-mode split - check the edition cited.

Further Reading

• GB/T 50500-2024: clauses 7.2.1-7.2.2 (measurement), 7.4.1-7.4.3 (variation measurement), 8.2.1 and 8.2.3 (defect adjustment), 8.9.1-8.9.3 (variation adjustment), 8.9.8 (omitted work), 10.3.2 (settlement items).
• Companion measurement per GB/T 50854; terms per GB/T 50875.
• The listing of item 9 ties into sections 10.3 - read together.