FlightPathOBN:
Yes Denti, that is correct, the 2 WAAS sats are CONUS only for WAAS RNP 0.3, and WAAS LPV, but you get some limited coverage down into S America., I dont know of any plans to float others.
Have you checked all of the LPV approaches in Alaska?
Also, Mexico has adequate vertical coverage, but the presumption is they would have installed a ground reference station. So far, "No Senior."
I suspect below Mexico it is like Hawaii, good horizontal coverage but lousy vertical.