Two situations

The first time you add a single item and the second time you add an order, a different payment number will be used. This can be distinguished in the ERP system as adding a single item instead of futures

Secondly, some models of colors A and B will be made into two colors of the same style of clothing. The colors are very tiny and difficult to see unless you are a professional. I don’t understand why they do this

Usually clothing companies sell the same model in different sizes, basically for these two reasons.