@binhvo- that is my experience as well. We had 4 ESPP sales to enter for 2020 and instead of using the import function, I manually entered the details of each sale by walking through the interview process four times. On each run though entering the data manually, TT calculated a cost basis on each sale that appeared to be reasonable (I just can't use the word correct there...) and I went with that.
Prior to doing this, when using the import function, the first ESPP sale seemed to calculate the cost basis but the second and third sales each had a calculated cost basis of zero dollars. I know that was not correct....
@TomYounghas commented on this issue in other threads and he seems to be a very busy lad around these parts. If I understood one of his posts on this issue correctly, that was what lead me to the solution I used above.
Whether that was right or wrong, one indicator I kept track of was to make sure TT calculated a cost basis of something other than zero for each sale.
Best of luck with this.
