I hope some can help me with my tax question with previous...

I hope some can help me with my tax question with previous experience rather than a general advice.
I received my commsec summary for year 2015-16. It shows Total Buy $85,000 and total sell $67,000. The list is made up of 30 transactions.

When my accountant was doing the tax return, he said I am more of share trader and he treated my trading style as a business. Therefore, he was saying my loss is about $-18,000 (i.e. 85000-67000 = 18000).

Is this correct a correct way?

Because I did not lose 18000 as some individual stocks are on "hold" status. My actual loss is about $2000 as I record all my transactions in the Excel.

The question is why they only look at Total Buy and Total Sell and their difference as some buys do not get sold within the same financial year but it pushes up the total Buy value up within the same financial ?