The difference between 1 cotton and No.2 cotton is that they meet different national standards. The average fiber length of 1 cotton is longer than that of No.2 cotton. In the choice of substitutes for futures delivery, high-grade varieties can replace low-grade varieties, but the price will be higher (higher than the delivery price), and low-grade varieties can also replace high-grade varieties for delivery, but the price will be discounted.

For example, Dalian soybeans, the delivery standard is third-class soybeans. If first-grade and second-grade soybeans are used, they can also be used instead of delivery, and the price will be increased by 30 yuan and 10 yuan (per ton) respectively. If you use fourth-class soybeans, you can also deliver them at a preferential price to 30 yuan.

The problem of cotton delivery substitution written by the landlord means that 1 cotton can replace No.2 cotton for delivery, but No.2 cotton can't replace 1 cotton for delivery, that is, high-grade cotton can replace low-grade cotton, and low-grade cotton can't replace high-grade cotton.