Well, I typically cook because I can make MUCH better food at home for a fraction of the cost of eating out. I'll also preface that I'm relatively picky about food and am generally unhappy with the food variety and availability here (I'd probably have left already if it weren't for Barrio Chino. But the lack has made me a damn good cook, so thanks Argentina). For arguments sake:
At most of the take out Chinese places in my neighborhood (looking at a menu I have from a place in Caballito, prices generally representative), an order of 4 spring rolls costs $11 pesos, a chicken dish ranges from $30-40 or pork/beef from 30-45, seafood up to 80, and 1.5 liters of soda another $11. So, while not expensive still $20+ pesos higher than your estimate, not including a tip. Besides that, I think most of the chinese food is pretty awful here (very greasy and loaded with msg). But that's just my opinion.
The fajita plates at Maria Felix/salto de las ranas (chain, same restaurant different locations and what I consider to be some of the better tasting mexican restaurant food here) for two people range from $106-144 pesos, plus margaritas which while I couldn't find on the menus or online, I imagine that if you got a regular house margarita (with Cuervo, which isn't real tequila) it would run at least $30 pesos, where if you substitute in real tequila (sauza, patron, etc.) the price would jump *considerably*. Throw in a tip and you're talking upwards of $100 per person, not per couple.
Asian food, well... two *years* ago (the last time I went to Green Bamboo--found their menu online but of course no listed prices) a spicy curry plate was running close to $70 pesos (portion for one with rice), and drinks were all between 35-40 pesos. The food and cocktails are excellent, but there's no way that anybody can argue the price is lower than any asian restaurant in the States (Thai, Vietnamese or otherwise, even fancy ones--which unfortunately they ALL are here, as any low-end here would be crap but I know I can get a really good plate of pad thai in the States for around $5, curry for 8-10).