call centers - cart before the horse?

I just got of the phone with an Amex representative. I am fairly confident that she is an Indian woman and most likely working out of a call center in India. Quite impressive since it means she is doing the evening or the night shift and I appreciate her willingness to work at odd hours.
During our conversation, she read my address back to me and recited a 6 or 7 digit zip code for me. I of course corrected my address. I am not bothered by this as much as piqued by this. Call centers, BPO's and the companies that hire them work hard to mask the fact that these employees are not from the US. So the intensive training program on American culture and accent. This is a no win game that I believe focuses on the wrong thing.

I don't care that her accent is excellent as much as I care that she does not realize that US has a 5 digit zip code. I find it amusing that call center reps are being trained to hide their identity and act instead of being trained on the "serving" end of "customer service". If he/she realises that I am trying to "change my address" and helps me get it done with courtesy and clarity then I don't care how authentic the accent is.

--disclaimer--
I understand that there are more than enough customers who are comforted by a familiar accent. I do buy the need for accent training but I think it should follow good service training not precede it.
--disclaimer--