Yep, I get that, I use 8 different carriers. The problem is dialing any number in certain rural exchanges in 308 (Nebraska) for example; 308-458, 308-487, 308-638 to name a few. Neighboring Centurylink rate centers connect fine.
This page on the FCC site leads me to believe I'm not alone, so the ruling is troubling.
Obi so far appears to completely block these exchanges, and while other VOIP carriers may complete perhaps 20% of the time (F9, callwithus, localphone, callcentric, didlogic), the delays and audio quality generally make it unusable. Landline and cell complete without issue.
I did submit a support ticket, but I have done so with each of the other carriers in the past and have never gotten anywhere.