In reality no map is 100%, and the edge cases are always problematic,
particulary when things like LATAs, NPA-NXXs, and zip codes are not
created originially representations of geographic area, but in actually
paths, i.e. wirelines or carrier routes (i.e. mail carriers). So these
are actually approximations at the best case.
I don't know of any telco that could actually do this until they actually
started engineering the circuit for some of the funky edge cases.