The Japanese invoice system does not allow for sales tax to be calculated on a sales order basis. Sales tax is required to be calculated per invoice.

When creating a project invoice, it is possible to select multiple sales orders and combine them into one invoice.

In this case, since multiple sales orders are combined into one invoice, sales tax must also be calculated for each invoice.

However, D365 does not support this calculation and is not compatible with the system, and should be modified.