"Regardless, this letter will not change that, it is too easy to prove the safety side of this because of the "agents" break down over time. They don't like to use the words "explosive charge"..... think TSA. "
So change the cutter not the whole unit.
Also, I agree since they are not TSOD the letter isn't applicable.
I just wanted to point out the some riggers are ready to repack old parachutes that the manufacturer says have a life limit but not old AAD that the manufacture decided to give a life limit so he could sell more AADs.