Hard to say.
For AEP-IGR for example you're looking at
Argentina Domestic Value Added Tax (DL) $35.40
Argentina Gross Receipts Tax (QN) $11.40
Argentina Security Tax (TQ) $0.40
Argentina Airport Tax (XR) $8.80
If I had to guess I would say that DL and QN don't apply to award tickets and TQ and XR do apply to award tickets, making the cost $9.20.
But it's very possible that I'm wrong and the only way to know would be to call AAdvantage and find out.
Either way, I don't think spending time on the phone running through lists of city pairs and then finding out 5he taxes is worth the money.
It would actually sound quite funny.
SF: I'd like to book a OW award.
AAgent: From where to where?
SF: DME-YKS-DME tomorrow and then the cheapest OW city pair anytime in the next year.
AAgent: I'm sorry sir, I've just been transferred to the SF desk and I'm not quite used to your ridiculous requests. Could you please be more specific.