Very much doubt that would be the reason for flagging your account. As was said, the short timeframe is far more likely the reason. I know its not exactly your case but image you app for Card A and then a day later get a raise of $3000 and then the day after that you app for Card B. No more an unbelievebale scenario and definitely not any kind of fraud in your case or this one. You omitted some income in the one app and included it in the other.
I don't think it has anything to do with your income. I think it's because of the applications being so close together. I applied about 2 weeks apart and was denied because they were so close. I just called the backdoor number, answered some questions and was approved on the spot. Let us know what happens!
Starting Score: 648They asked me about my income. They asked me what my monthly payment is on my Amex (I pay in full monthly so it varies and I told them that - thought the question was a little odd). She put me on hold a couple times and came back and asked what kind of credit limit I wanted and then approved me. Call them! They're really nice...at least in my experience (and I've dealt with them numerous times!).