NO, PO box is not accepted.
Flowroute must provide a customer with the proper means to report state and local taxation. Incidentally, the use of a Post Office (PO) Box for tax determination geocoding is not supported. PO Boxes are not considered acceptable by tax jurisdictions for tax-suiting purposes.
For example, Street Address “PO Box 100” or “P.O. Box 58912” will not be geocoded.
Geocoding assists with our customer protection for keeping customer taxation distinctly within their tax location and removing potentially "higher than necessary" taxes on the usage of the account.