I'm curious, are you on the old plans or Mobile Share? Also, do you have unlimited data? I think this might be a tactic to get people to switch plans. I'm on Mobile Share and 2 or our lines are already eligible for full subsidy despite a contract end date of 9/21/14.
In your case, the difference is that my contract actually ends 9/21/15, but AT&T pushes up the end of contract eligibility to the first of the month, i.e. I'll probably really be eligible 9/1/15. They do not do this for the early upgrade anymore, it stays as exactly 1 year from original purchase.
To answer your question, yes I'm on an old FamilyTalk plan with unlimited data, and yes this is 100% an attempt to push people to NEXT, the manager basically admitted as much to me.