post your accountant's working paper, with out it no one know how he come to the conclusion of the final number. this question only an accountant can answer.
Assuming you had paid for his service, then it is up to him to educate you.
a how much did you buy the share and how much did you sell it for. We don't know that, then how are we to work it out?
there is also errors in your way of communication, is it 20000 shares that you are wotry about being the opening post or are you worry about paying tax on 20k profit which is not there?
