LadyHLG-
Eureka! I removed the excess zen cart tax definitions and tax rates and everything is working as expected except for:

Zip codes in range of "89830-89835;" is not being recognized by the local sales tax mod. I thought I could use the hyphen to specify range. However, "89830-to-89835;" works fine.

And, here's another problem: If I don't have a Nevada zip code defined (let's say the Post Office adds a new zip code and I am unaware) - no sales tax is charged (of course).

Is there a way to specify all undefined 89xxx zip codes should default to a minimum 6.85% sales tax within the local sales tax mod? Or, can I add one general Nevada zen cart tax rate and give it a lower priority (somehow) so it kicks in if the local sales tax mod doesn't find a matching zip code in its database?