In Oregon and California, a judge actually ruled that we were employees, which led to the settlement. So the question of being an employee has been settled.
I have read (for years) about filing an amended return, and it seems unclear. You can only claim a refund going back 3 years, and the IRS can only force payment if intentional fraud was committed after some period of time. I think that having filed the lawsuit in 2006(?) may have preserved some of that time if even needed. Whether I would owe any taxes is a close call. I paid more % in Social Security taxes as self employed but on an income that was calculated after expenses instead of before taxes. I think that because my net income after expenses was about 1/2 of gross, that by paying 15.3 % on my net in FICA tax(SE tax) it will end up being about the same as if FEDEX deducted the standard 7.65% from my gross.
From fedex perspective, they should have been paying their employer share of FICA taxes based on they gross I was paid. I think that if I filed amended returns, and the time frame was shorter, the IRS could demand that fedex pay those taxes.
For anyone still doing this Fedex ISP scam, and getting closer to retirement age, it would be smart to look at the effects of paying SS taxes on a lower income. It could mean 100s of dollars difference every month after retirement. My years at fedex were relatively short and well before retirement age, so it may not even make a difference. but if you are near retirement and short on previous earnings used to determine SS benefits, you might be well served by amending your returns for the prior years.