An identified cloth is sold as “200 cubits, total 200 dirhams.” If this is a lump-sum sale of the whole cloth and it is 225 cubits, the entire cloth goes to the buyer at the agreed total.
If the sale instead expressly says one dirham per cubit, the buyer can take all 225 for 225 or rescind.
The same extra 25 cubits are treated differently because the contractual pricing was different.
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Kitab al-Buyu: Shortage, Surplus, Buyer Options and Price Allocation
An identified cloth is sold as “200 cubits, total 200 dirhams.” If this is a lump-sum sale of the whole cloth and it is 225 cubits, the entire cloth goes to the buyer at the agreed total.
If the sale instead expressly says one dirham per cubit, the buyer can take all 225 for 225 or rescind.
The same extra 25 cubits are treated differently because the contractual pricing was different.