Funnily, while TurboTax "Tax Expert" is ignoring what we have pointed out regarding the IRS rounding quote, I found this from a different tax filling option, Tax Act: https://www.taxact.com/support/1183/2017/form-1099-div-rounding.
Apparently they also round each sale transaction, but they used the total provided in the 1099 form (in this case 1099-DIV, but I would say it's similar in case of 1099-B), not computing from the rounded transaction line like what TurboTax is insisting on doing. Therefore, the final amount is corrected and same as what reported on 1099.
If you haven't filed, probably move your business somewhere else, and get your refund on TT software if you can.
