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Why is tax calculating in Sage 100 even though my customer is exempt?


We did not have a customer's exemption certificate, when we originally invoiced them. The exemption certificate has now been added into Avalara, and we attempted to do a credit memo in Sage 100 (MAS 90). I have been unable to get the tax to appear again for the purpose of doing the credit memo. I revoked the certificate and deleted the certificate # from MAS-100, and the tax still won't appear. I have been able to perform the same process successfully for another account, but can't figure out what I am doing wrong for this one


Sage 100 (MAS 90)


  • When making creating a Credit Memo in Sage 100
    • Make sure to only have one line for each line item you are crediting
    • That your passing them as POSITIVE line amounts
    • The nature of it being a credit memo in Sage will send the information to Avatax, as a negative line amount.