Here are my thoughts:
- I don’t think using an integration partner like Avalara should be a requirement to be able to use this functionality. Avalara isn’t absolutely required to get tax rates although I’m sure it streamlines the process somewhat and some customers use it.
- In the US, sales taxes may be owed at the metropolitan area/city, county, or state level. This can have an impat on the overall rate at state level, if there is a rollup of these.
- It is possible for an incorrect rate to have been applied on a given transaction or even multiple transactions OR tax rates may not have been setup for a new jurisdiction in time; so rates may need to be changed for multiple customers or invoices for a customer, or it may need to be dealt with just moving forward. A timeframe may be needed to be selected as to the scope of any changes due to rate changes and/or effective date of the rate.