Thanks for this. I also have a client who did an exer-sale of ISOs during 2020. 

Your info about the disqualifying transaction is helpful.  I am entering this as an exercise of NSOs, and the bargain element is showing up correctly on his W-2, so all is well there. 

Just one more procedural question: In ProSeries, I entered the exercise on the "Exercise of Stock Options Worksheet."  But where do I enter the SALE of those same shares?  The worksheet specifically says that section is for options exercised and held (not sold) in 2020. 

Thank you!