When you talk to the Audit Defense people (and I suggest calling them because they will be able to answer all of your questions), you can buy the full audit defense, but it only covers you for any IRS letters received AFTER the day you buy it. So if you already received an IRS audit letter for a tax year where the Audit Defense expired, then buying the perpetual version direct from Audit Defense is not going to get you coverage for that letter. I think I recall that they can still represent your case, but it costs $2500 or similar.
