Hey Zenners!
Apparently there are some issues with the local tax mod and zen cart version 1.3.9. I have not yet figured out what is going on (it really is only evident when gift certs are involved as far as I know, but I have not done extensive testing as yet.)
Until I figure out what is happening, I can not recommend the use of the Local Tax Mod with Zen Cart version 1.3.9.
When i have more to report I will let everyone know.

LadyHLG