Manage has a “Tax Code”, and a Tax Code can have multiple “Levels”. Similarly, Sage 300 has “Tax Groups”, and a Tax Group can have multiple “Tax Authorities”. The Manage Tax Code and Levels correspond to the Sage 300 Tax Groups and Tax Authorities, respectively. You will need to ensure that you fill in the Tax Code XRef and Agency XRef for EACH level you use.
When dealing with “Tax Exempt” tax rates, you will still need to fill the first Tax Code XRef field to match the Tax Group in Sage 300, but leave the Tax Agency XRef fields blank. The following is an example of a Tax Exempt setup: