TAX_CODE_ID is null -> interface -> but tax code is not null

Currently TAX_CODE_ID is in AP_INVOICE_LINES_INTERFACE is null, if customer interface it. the value will be created. So they have to delete it. it's very complicated

Customer want to know how to set up to avoid it.
that is if TAX_CODE_ID is null. and after interface , the value is still null

could i tell customer to set Allow Override of Tax Code profile option is unchecked and TAX_CODE_OVERRIDE_FLAG이  NULL orNo,

Is it ok?


Thanks.