"So I
guess my question is changing a bit...since I was never taxed on the
15% discount because I was retired when I sold these, should I just use
the price I paid for the shares - which would be the 15% discounted
price?"
This can't be answered "Yes" or "No" because for qualified sales compensation is calculated as the lesser of two numbers:
The first is the discount allowed on your purchase, determined as of the "grant date," which is normally the first day of the offering period. Note that this is not necessarily the actual discount you received on the shares. It's the discount determined as if you bought the shares on the grant date, even though you didn't buy the shares that day and couldn't have done so even if you wanted.
The second number, which comes into play only if smaller than the first one, is essentially your profit from the shares. More precisely, it's the difference between the fair market value of the stock when you disposed of it and the actual amount you paid for the shares.
You can use the ESPP interview to report the sales, referring to your Form 3922 information. TurboTax will calculate the compensation and add that amount to your out of pocket cost. When you're done entering trades work through to the bitter end of the "Stocks, Mutual Funds, Bonds, Other" interview. You'll eventually come to a page titled "Your Employee Stock Plan Results" where TurboTax will ask if the compensation has been reported on a W-2.
Tom Young
