إن شاء أخذها بجملة الثمن وإن شاء تركها
Translation: If the buyer wishes, the buyer takes it for the entire stated price; otherwise the buyer may leave the sale.
Suppose an identified cloth is sold for a lump sum of 10 dirhams, represented to be 10 cubits, but is found to be 8 cubits. The buyer may:
1. Accept the same cloth for the entire 10-dirham price.
2. Reject the transaction.
The buyer is not automatically entitled to pay 8 dirhams in this particular contract structure. That is the key difference from the measured-grain case.