Maryland has only a state rate of 6% and an invoice has 1 line. Why didn't AvaTax round the tax down?
Sales tax rates in Maryland and Florida are based on a bracket tax system for certain goods and services. The amount of a taxable sale is cross-referenced with the associated sales tax due for that bracket.
AvaTax automatically applies the appropriate rounding logic for these states. Learn more about these bracket systems over at the Avalara blog.