I've only just read this thread. I guess you wont be buying them again?
Using older hops was discussed before in a thread. I think, the problem you would have had trying to work out how much AA% is left in the TnT hops, is that it's a blend. Different hops deminish a different rates and even if you knew which hops were in the blend it would have been a nightmare trying to work out the overall IBU's
You're right there - I probably won't be buying these again, but it would be interesting to have some from the latest harvest to see if there was a difference.