Weightier docket?
Look at what the rehearsal actually did before you blame anyone: it opened the carton, weighed the contents, added protection and sealed it again. A 1.4 kg hoodie order that weighed 1.4 kg on arrival printed a 3.0 kg ticket after compression packing on one of our recorded jobs, and the 1.6 kg difference was air volume plus two sheets of corner board rather than a missing item.
The change looks suspicious because the figure moves in the direction you did not ask for. Compression packing is a service that reduces volume, and the service notes emphasise that volume falls; they say nothing about scale weight, which rises by the mass of whatever was added.
Enter the sealed carton size in centimetres, divide the volume by 5000, 6000 and 8000 in turn, then round each result up to the next 0.5 kg, because one box carries three possible volumetric figures. On a 52 by 38 by 24 cm carton the raw volume runs to 47,424 cubic centimetres (Recorded), which returns 9.5 kg at a divisor of 5000, 8.0 kg at 6000 and 6.0 kg at 8000, so identical contents print a ticket anywhere between the 6 kg row at £34.80 and the 8 kg row at £43.60 (Recorded). 1. Pull the rehearsal dimensions and the divisor from the packing log before you argue about the weight. 2. Recompute the volumetric row at all three divisors and mark the one the warehouse actually used. Our re-checks explain most of the shock: 3 of the 12 rate snapshots taken between 2026-08-01 and 2026-10-02 left the divisor unstated, which makes their volumetric rows impossible to reproduce and leaves a heavier ticket unattributed in either direction (Not verified); the rehearsal photo shows the board that went in, but it never shows the divisor that was applied.
Truthful figure
Two effects run at once and only one of them is on the receipt. Packing material adds 0.10 kg to 0.45 kg of scale weight depending on how many boards were used, while folding reduces measured volume. On a 40 by 30 by 18 cm carton the volumetric figure starts at 3.6 kg; drop the height to 14 cm and it falls to 2.8 kg, which is a 0.8 kg reduction on the row that usually drives the bill.
1. Pull the before and after dimensions for the same parcel from the warehouse log. 2. Recompute the volumetric figure at both heights with the same divisor. 3. Compare the chargeable figures, not the scale weights, because the scale weight moved the wrong way on purpose.
Compare the settlement line rather than the ticket weight, because the honest figure for a parcel is what leaves your balance. Our recorded £120 job carried goods at £84.60, domestic freight of ¥12 plus ¥8, line freight of £20.00 on a 3.8 kg chargeable figure at £5.26/kg, a service fee of £6.13 at 6% of goods plus domestic freight, packaging at £3.50, and a settlement of £108.34, while a £40 order in the same sample closed at £48.75 and a £210 order closed at £167.93 (Recorded). 1. Write five rows, covering goods, domestic freight, service fee, packaging and line freight, then convert the yuan rows at the settlement-date rate. 2. Subtract credits before comparing two parcels, because a credit that lands on day 4 leaves the day-1 figure looking complete when it is not. Where those rows reconcile, a heavier ticket becomes an explained line; where they miss, the gap is normally a storage charge or a credit still in transit, and a £40 job that settled £8.75 above its headline figure shows how little the headline tells you (Recorded).
Boundary surcharge
The damage concentrates at tier boundaries. A parcel measuring 4.9 kg after packing sits in one tier and a parcel at 5.1 kg sits in the next, so 200 g of board can trigger a jump of £5.40 on a line whose 3 to 5 kg tier runs at £26.40 and whose 5 to 8 kg tier runs at £31.80. At 4.9 kg the board is nearly free; at 5.1 kg it is the most expensive material in the carton.
1. Ask for the post-packing dimensions before you settle the freight. 2. Run the figure through the shipping-bands gauge and read the distance to the next tier up. 3. If the parcel sits within 0.3 kg of a boundary, request a lighter board or a smaller carton before it leaves the packing bench.
Round the volumetric figure up to the next 0.5 kg before you compare it with scale weight, since the ceiling step can lift a parcel across a boundary that the raw number sits below: a raw 5.04 kg becomes 5.5 kg, and the band above the 5 kg edge is where our recorded 5.1 kg parcel sat at £31.80 (Recorded). The edges we work to are 1, 2, 3, 5, 8 and 10 kg, spread across 6 routes and 9 bands from 0.5 kg upward, while the flat stretches matter just as much, because the 8.0 kg and 8.5 kg rows both quoted £43.60 and the 10 kg and 11.5 kg rows both quoted £54.60 (Recorded). 1. Note how far your ceiling figure sits from the next edge. 2. Strip board or height when that distance is under 0.5 kg, and keep the protection when you are already inside a flat stretch such as 8.0 to 8.5 kg. Rehearsal packing is the moment to check this, because the carton is still open: 2 cm off the height costs nothing on the bench, while the same 2 cm measured after sealing is already priced into the band.
Edges move as well as parcels, so two further rows belong in the rehearsal notes: the rate table the parcel is priced against, and the storage clock that keeps running while the carton sits on the shelf. Across 12 rate re-checks between 2026-08-01 and 2026-10-02, 4 showed the same route's first weight rising, the largest by £1.60 (Recorded), and 3 of those 12 snapshots left the volumetric divisor unstated, which makes their figures impossible to re-derive (Not verified). 1. Log the inbound scan date, because the free storage window starts there rather than at payment. 2. Diarise the last free day and compare the release date against it, since the overdue figure in community threads is £0.20 per item per day (Community-reported). In our sample 8 of 24 items ran 1 to 14 days past that window, and a 14-day overrun on the same rate reaches roughly £2.80 (Community-reported); a dark rim on a rehearsal photo is weak evidence of damage, because 5 of the 6 edge and border marks in our QC log turned out to be lighting artefacts (Recorded).
Airier docket?
The opposite reading fails just as often, and it fails in the expensive direction because it stops you looking further. A parcel whose scale weight fell from 3.6 kg to 2.4 kg after compression looked like a 1.2 kg win, but the volumetric figure only moved from 3.6 kg to 3.4 kg, so the chargeable figure stayed at 3.5 kg and the invoice did not change by a penny.
Compression attacks dimensions while the invoice follows the larger of two figures. When scale weight was already the driver, folding the contents cannot help at all, and the honest entry in your notes is that the service was neutral on this parcel rather than that it saved 1.2 kg.
Cutting a carton down does lighten the ticket, but only when the reduction crosses a whole 0.5 kg ceiling step: moving from 6.02 kg to 5.98 kg shifts the row from 6.5 kg to 6.0 kg, while 6.42 kg down to 6.02 kg changes nothing. Work the height first, because it is the dimension that falls fastest when contents compress, and stop the moment the ceiling figure lands on the step below, since the gap between 6.02 kg and 5.98 kg is 40 g and no eye can see 40 g on a sealed carton. 1. Compress to the next 0.5 kg step and no further, because the table rewards nothing beyond it. 2. Record the before and after figures side by side, so a neutral rehearsal is written down as neutral. The other lever that genuinely lowers a ticket is the credit row: 14 credit events sit in our records, 9 of them inside 3 days and the remainder inside 11 days (Recorded), while 2 codes were refused in the same window with no reason recorded and should be planned around until a written explanation arrives (Not verified).
Stiffeners opposed cavity
Write the two effects on separate rows so you can price them independently. Our record covers 24 parcels between 2026-08-01 and 2026-09-30, of which 9 had a packing service applied; on those 9 the dimension reduction removed 0.4 kg to 1.6 kg of volumetric weight and the materials added 0.10 kg to 0.45 kg of scale weight.
1. Note the material mass in kilograms as a cost you chose. 2. Note the volumetric reduction in kilograms as a benefit the line recognises. 3. Subtract the second from the first only when volume was the driver, and write the parcel off as neutral when scale weight was already on top.
Three measurements concur
Three measurements answer the question for one order, and none of them needs a chat with support. Measure the sealed carton yourself when it arrives, since outer dimensions are unchanged by transit; line that against the post-packing figures in the log, and compute the chargeable weight at your line's divisor.
Where the numbers disagree by more than 0.5 kg, treat the gap as a records question rather than a dispute. A 0.5 kg gap is one rounding step at a divisor of 6000 on a mid-size carton and is the most common innocent explanation; a 2.0 kg gap on a 40 cm carton is not a rounding artefact and deserves a written query with both sets of dimensions attached.
The data point behind this note
Of 9 recorded parcels that had compression packing applied, the volumetric figure fell by 0.4 kg to 1.6 kg while the scale weight rose by 0.10 kg to 0.45 kg from packing materials (Recorded).
Rates last checked 2026-10-02. Where a figure is community-reported we say so; where we could not verify it, we write Not verified instead of estimating.