I've actually been seriously considering adding a pay as you go plan, where you pay for only per the number of requests you make,is this something that would interest you? The current prices are an extended Cyber Monday offer, I figured I'd let it run into the holidays.

Unfortunately it's never going to be spot on all the time.

Awesome points on the example ips and adding error handling documentation. Thanks for pointing me to rfc5737!

I'm adding the Error Code documentation right now.

Added a table with Error Codes and their accompanying messages.