I answered the same question here, four years ago. Except I should have written "I'm guessing that its public-safety workers are NOT covered by Social Security,"

 https://accountants.intuit.com/community/proseries-tax-discussions/discussion/excludable-compensatio... 

In any case, the only taxpayer who can rely on a Technical Advice Memorandum is the one who asked for it.  It doesn't appear that you even have the correct reference number for it, so good luck.