Thank you SO MUCH for posting this. I had the exact same issue and trouble. I was with a live expert for about 20 minutes without any success. In the end my search came up with your post on how to get the correct information into line 8.a. This information is important (assuming not $0) because otherwise your reported stock basis at the end of the tax year will not be correct and could get flagged the following year.
Again, a big thank you to @richlux
