Mistake 1: Automatically reducing the price for every shortage. A lump-sum cloth case differs.
Mistake 2: Treating surplus measured grain as a free benefit for the buyer; the surplus remains the seller’s.
Mistake 3: Assuming the original total is unchanged despite an explicit per-cubit price and extra cubits.
Mistake 4: Ignoring the buyer’s stated option and compelling acceptance of a changed bargain.
Always read the exact contractual wording before assigning a result.