In the financial transaction records of the balance of payments, the data recorded according to the total amount is very huge, and it is difficult to get very accurate data.

For example, the foreign exchange trading volume exceeds German GDP. Such data is of little significance as stock data, and it is difficult to find such data accurately. So you must record the party according to the net amount.

Type record, so that all links in the middle can be washed away.

Residents and non-residents pay different taxes and can be distinguished according to the net method.

If the gross record method can't be expressed intuitively, for example, everyone earns one,

Because taxes are different, the final effective results are different.