Tax Correspondence, Invoice Lines - Manual Postings
If you select this checkbox, the system will validate that the total net amount posted per tax code equals the total net amount of the invoice lines per tax code. This validation is performed when entering postings manually on a Manual Supplier Invoice or a Manual Customer Invoice as well as in External Customer and Supplier Invoices. Tax correspondence functionality is only applicable for single tax code per line item.

Thanks for your feedback and exact information could be found on help text as well. Yet my query is on, any other functional impacts other than system not letting users to enter multiple tax lines.?