Different fares are not a surprise - peak (as mine were) vs non peak, convenience (e.g. 440 am versus daytime to Calafate), early booking, sales, LAN vs Aerolineas all make a difference.
My question is the one noted by NickB - is there any way of avoiding the double whammy of non resident fares at the official exchange rate? My interpretation of the answers is that there isn't - you can't pay cash pesos as a non-resident, and all booking engines use the non-resident peso fare and convert it at the official rate. (As a matter of interest ITA does pull up resident fares but these aren't bookable and the rules clearly state that they are for locals).
My personal response to this is to switch to Mendoza for this trip, using British Airways Avios for BA-MDZ on LAN at 9000 miles + $60 return. Next year I'll return and book BA-Calafate many months in advance in an off-peak month for 18000 miles + about $80 return. As the figures above show, Argentina is the really sweet spot of Avios.
Last edited by carbonaddict; Jan 19, 2015 at 12:17 pm