Validity of the tax code in OBCD

Hi Team,

Please can some one share their expertise on OBCD settings.

The requirement is to have a validity date field in the table T076M, the issue is if there is a change on the percentage of tax code or we create a new entry on to this table the Idoc is not able to read the correct tax code and will end up in getting the old tax code been calculated while posting the billing document.