Update:
Asuncion flight landed on tarmac at AEP with shuttle bus to immigration area. First guy tried to push me through to immigration line, when I asked him in Spanish "What is that sign for International Connections with a red arrow?" He gestured for me to head that way where a woman checked both of my boarding passes, indicating to go up nearby stairs (my suitcase was kind of heavy, with a down escalator, but up was stairs only 🙄
. A very bored guy at the top (think: Maytag repairman) ushered me through a metal detector, bags through X Ray machine. I buzzed loudly; he gestured for me to grab my bags, practically shoving me through the door he opened into International Departures. 😀