That is for sure not true in my case.
I have hundreds of option trades with Vanguard. Vanguard charge you $1 commission for each written or bought-back contract and, only for each written contract, a small fee which is in all my cases lower than 50 cents.
That means that the amounts of all my buy-backs are always in whole dollars and the amounts for a written option contract are always less than 50 cents smaller than a whole dollar amount. The result is that all my profits (and losses) are always less than 50 cents below the whole dollar amount (Just by the fee amount).
TurboTax round all these profits (and losses) up, basically it ignores my paid fee. In my case, that made my gains $ 76 higher than they really were. The averaging out with more transactions works only if the fees would have a uniform distribution from 0.1 to 0.99 cents. In my case, more trades would only result in a larger rounding error.
