6 weeks ago I flew to Quito, though BOG, then to Guayquil and back to Bogota on an Aeroplan 014 ticket.
So, BOG-UIO-GYE and then UIO-BOG were all on Avianca.
I called Avianca last fall and paid to be put in the first three rows (we are 4 PAX) on all the Avianca flights . It cost me maybe $30 per seat per flight and we got priority boarding plus a 2x2 seating configuration (similar to intra-Europe Business Class seating).
I had no problems getting through to Avianca on the phone and no problems getting the seats assigned. Is it because I was paying??? I dont know.