Keep the inclusive merchandise base
At the observed one-carton inclusive prices,one 3758B,one TTR001 and one 102 give£68.38 merchandise. The ledger converts validated GBP strings to integer pence before multiplying whole-carton counts. This avoids letting floating-point drift decide whether a credit is exactly equal to the base.
Allow exact full credit
A confirmed merchandise-only credit of£68.38 leaves£0 merchandise. A£68.39 credit exceeds that base and is rejected. These are arithmetic tests,not live vouchers,credit-note validation or an assertion that a supplier accepts any entered promotion.
Retain shipping and other charges
Shipping,confirmed additional tax and other charges remain after the merchandise credit. A test entry of£4.99 shipping and£1.25 additional charge leaves£6.24 payable after full credit. These test amounts are not a supplier’s observed fee schedule. A blank charge keeps the full total unresolved.
Reject invalid money and quantities
All default selected quotes are already inclusive;do not add the same VAT again. Negative amounts,more than two decimal places,exponent notation,fractional carton quantities and inputs beyond the stated limit are rejected. The tools do not transmit orders,customer records or payment information.
Apply the field to a purchase
The additional money-boundary test£47.99 times two gives exactly£95.98,and£0.10 times three gives£0.30. These tests check integer-pence handling;they do not introduce new observed roll prices.
Sources & scope
Checked November 5, 2026. Manufacturer and retailer references support the specific statements. Dated displayed prices are not final checkout quotes, performance rankings or performance testing. This shopping reference does not replace the exact product label or retailer instructions. Current received labels and independent printer/media/material/content/commerce review remain pending.
POS Central UK3758B20-roll80m offer ↗