The mistake
Somewhere in a chain of formulas, one cell holds a typed number. Usually it began as a quick fix: a total pasted in as a value to try something, or typed before the cells that should feed it existed. It was right on the day.
Then the tab is copied for the next offer, or the price changes. Every formula recalculates and the typed cell stays as it was. From there on the sheet mixes two offers: the costs of the new one against the revenue of the old.
A worked example
A three-bottle offer built by copying the single-bottle tab. One bottle of supplements is $37.95 plus $9.29 shipping, $47.24 in all. Three bottles at 10% off each are $102.48 plus shipping, $111.77.
On the copied tab the quantity is changed to three, so the unit cost, the picks and the heavier label all update. The "customer pays" cell is a typed $47.24 and doesn't. Card fees and the refund reserve are percentages of it.
The sheet shows the three-bottle offer losing $2.86 an order, a margin of -6.1%. With the total computed from the price and the shipping, the order keeps $56.57, or 50.6%.
| Line | The sheet, total typed | Total computed |
|---|---|---|
| Customer pays, with shipping | $47.24 | $111.77 |
| Unit cost, three bottles | −$31.41 | −$31.41 |
| Pick and pack | −$4.16 | −$4.16 |
| Shipping label | −$10.50 | −$10.50 |
| Card fees | −$1.67 | −$3.54 |
| Refund reserve | −$2.36 | −$5.59 |
| Margin | −$2.86 | $56.57 |
| Margin % | -6.1% | 50.6% |
The order's figures are computed by the margin engine in Offer Suite's own code, in whole cents. The sheet's are the same order with the mistake applied.
What it does to the decision
A negative margin gets an offer cancelled, and this one keeps more than half of what the customer pays. The reverse case is worse because nothing flags it: a typed total that is too high shows a healthy margin on an offer that loses money, and the offer ships.
Typed cells are hard to find. They look like every other cell, and the sheet's own totals agree with them.
What prevents it
In Offer Suite nobody types what the customer pays. An offer document states the product, the quantity and the discount. The charge is computed from the store's catalog price by the same pricing rules the buy box uses, and the margin is computed from that charge.
Before the offer goes live, publish builds a real cart for every visible option on the store and compares what Shopify charges with what the offer promises. A total that disagrees with the price, in either direction, stops the publish.
A spreadsheet is still the right tool for some of this. Where it is, and where it stops: Offer Suite vs a spreadsheet.
Where the numbers come from
The example is not a real brand's offer. Every input is sourced below, or marked there as an assumption.
| Price | $37.95, a bottle of supplements. Nature's Sunshine homepage, read 23 September 2026 |
|---|---|
| Unit cost | $10.47. Nature's Sunshine, fourth quarter and full year 2025 results, read 23 September 2026 |
| Refund reserve | 5%, Offer Suite's default assumption for consumables. NRF's all-category figure for online sales is 19.3%, but consumables are rarely returned; use your own rate. |
| Pick and pack | $3.20 per order and $0.48 for each extra item. Fulfill.com, 3PL pricing benchmarks (The Fulfillment Advisor 2025 survey of 600+ warehouses), read 23 September 2026 |
| Shipping label | USPS Ground Advantage, commercial, Zone 5, by weight rounded up to the pound: 1 lb $9.29 · 2 lb $10.50 · 3 lb $12.12 · 4 lb $13.89 · 5 lb $14.53. Packed weight is an assumption: 0.5 lb per unit. USPS Notice 123, USPS Ground Advantage Commercial, Zone 5 (effective 4 October 2026), read 13 October 2026 |
| Card fees | 2.9% + $0.30 per order: Shopify Payments' online rate for a standard card on the Basic plan in the United States. Higher plans pay a lower rate, and premium cards a higher one. Shopify's pricing page for the United States, online standard card rates, read 12 October 2026 Rates by plan and country |