It's pretty simple really, 90% of your shipments will be going to the highest zones (mostly 5 & 6 I think), the differences are tiny anyway, just use the highest rate zone and go from there.
If you really want to adjust all those packages you're sending to the Jamaica and Mexico you can refund the 15 cent difference.

"What else could I do? I had no trade so I became a peddler" - Lazarus Greenberg 1915
- answering Trolls is voluntary, my policy is not to participate.

"What else could I do? I had no trade so I became a peddler" - Lazarus Greenberg 1915
- answering Trolls is voluntary, my policy is not to participate.