I did the rational thing and contacted Avianca directly:
Derian: If you have thought to buy in this days, let me inform you that the restrictions for Peruvian or non Peruvian Residents does not applies, can apply if you have a ticket which was purchased before of February the 5th, in that case if the ticket was purchased before that date, the penalty of $178.50 USD can apply, but if you want to buy now, the restriction does not applies and you can buy the fare you want, without have to pay overcharges.