If zip+4 will sort to the correct block, and correct side of the road, there will certainly be a strong correlation between zip and sales tax.
The above may be true in the area you live in. (Not in a big city) Some roads run East-West & North-South)
You are standing in the middle of Wilshire Blvd (Runs East - West) in OKC at aprox. 8900 NW or 8901 NW.
County Line Road is the Boundary between Oklahoma & Canadian Counties.
The question: Is County Line East or West of you? (Answer: It is both, East by 125 Feet & West by 125 Feet)
Bonus Question: Name the only two section lines that run north & south in Oklahoma (Indian & Cimarron Meridian)
You can have a Yukon Zip Code (73099-XXXX) and live in Canadian County but live in OKC City Limits.
Or a Yukon zip code and live in Oklahoma County and vice a versa.
You are standing in the middle of Wilshire Blvd (Runs East - West) in OKC at aprox. 8900 NW or 8901 NW.
County Line Road is the Boundary between Oklahoma & Canadian Counties.
The question: Is County Line East or West of you? (Answer: It is both, East by 125 Feet & West by 125 Feet)
Bonus Question: Name the only two section lines that run north & south in Oklahoma (Indian & Cimarron Meridian)
You can have a Yukon Zip Code (73099-XXXX) and live in Canadian County but live in OKC City Limits.
Or a Yukon zip code and live in Oklahoma County and vice a versa.