Income tax types not populating when matching PO to Payables on all lines

 We use PO matching for payables.  The supplier is correctly setup with the Federal flag checked and the Income Tax Type listed.  The code correctly populates on the material distribution lines every time.  However, on the sales tax and freight lines, sometimes it does and other times it does not even with the same vendor.  What is causing this?  What is the best way to fix it without doing manual updates?