I have this same problem. Whenever an upgrade clears, they almost always assign an aisle seat, even though my profile has "window". Recently, the EXP desk was adding an upgrade request to my record, and asked whether I prefer window or aisle. I had to laugh, because this feature hasn't worked properly for years. The AAgent told me that it will work, if you know how to request it correctly. I thought she was joking. But lo and behold, when that upgrade cleared, it assigned a window seat. Coincidence? Hmmm, what do THEY know that WE don't know?