APO and FPO addresses do seem to be recognized by AA as being CONUS addresses. Not a major problem for most, but it can become problematical for credit card addresses that do not match charge requirements, when one passes the 2M threshold and gets more 500-mile stickers (I'd consider getting a local address, and it is not cheating in any way to declare a local German address if living in Germany, for instance.)
AA's system is like an onion, with many layers superimposed on the original layer of programming. Look at the differences: years to show eVIP/SWUs in one's account, batch processing for travel and other miles rather than real time, etc. We may be past the "Semi-Automated Business Research Environment" days, but there's quite a bit of AA's IT processing that remains stuck in the past. AA, AE and AP may as well be in Antarctica for AA?
From Wikipedia:
• AA (ZIPs 340xx) for Armed Forces (Central and South) Americas)
• AE (ZIPs 09xxx) for Armed Forces Europe which includes Canada, Middle East, and Africa
• AP (ZIPs 962xx - 966xx) for Armed Forces Pacific