Sample user exit considerations: yFSRecalculateHeaderTaxUE
The YFSRecalculateHeaderTaxUE user exit allows you to compute order header taxes using custom logic that differs at the document type level.
If an order requires invoiced tax, then YFSRecalculateHeaderTaxUE should be implemented to distribute the tax among the invoices. You must specify a tax percentage unless you are using the YFSRecalculateHeaderTaxUE to pass the amount from an external system.
For details of the input and output structure of YFSRecalculateHeaderTaxUE or any other user exit, see Javadoc.