UPS shipping - can't figure it out

Well, I have figured out how to ship UPS from my Tindie account (using What I haven’t figured out is how to price it. Since Tindie has a blanket shipping cost by country, I can’t easily map onto the UPS zones for the USA. I’m USA based, fwiw.

So, I need to create a price that is high enough to cover the entire USA. I went through the process of estimating shipping cost to previous customers and then spot checked different areas of the country. I then looked up UPS pricing/zones/… and it really doesn’t match up with the costs I found in spot checking. 3 different addresses in a zone (east coast USA) have different prices and the closest one to me is the highest. Surprisingly, the deep woods of Maine was cheaper than a location in Rhode Island 40 miles from Providence.

Does anyone have some insight to this? I’ll go with the worst case price but I’m not even sure that is truly the worst case. I guess if I lose money on shipping, I’ll jack the rates again. Kind of hate doing that to my customers.