Thank you, JamesG1,
I think I figured out what's wrong with the TurboTax, and I think it needs to be fixed. The scenario you presented is exactly what I have though I have close to 20 transactions to report to for one 1099-K, and that's what seems to be causing the problem.
I perfomed exactly the steps you mentioned except that in Investment Income area I entered all transactions including losses. I believe this is required since IRS requires reported all the transactions including losses even though only profitable transactions are taxable and the rest are treated as zero profit.
When I do this, Schedule D shows the correct sum of all the profitable transactions (= $400 in your example), and Form 8949 on the Turbo Tax Home and Business screen Column (d) shows the correct proceeds total after adding Part I (Shor-Term) and Part II (Long-Term) totals (= $1,000 in your example) and Column (h) the correct sum of profitable transactions (=$400 in your example). So, all tax forms look correect on the screen.
However, when I print out the form for submission, Form 8949 shows only the first 14 transactions for this 1099-K and the total is only for the first 14 transactions. Thus, the amount in Form 8949 printout is different from Schedule D.
Smart Check which says the proceed amount in the worksheet does not match with 1099-K ($500 in your example) even though they actually match for the taxable amount. I initially thought it was comparing taxable 1099-K portion against the total worksheet amount including loss transactions. But it now seems to me the error due to 15+ transactions for the same 1099-K.
Shig
