I have a 1099-B containing a large number of sales of RSUs, so entering them one at a time would be extremely time-consuming. So it would make sense for me to enter the proceeds total and cost-basis total.
But, TurboTax has this warning that says, "We strongly suggest entering sales one by one" "Entering sales one by one can ensure your best outcome." And when clicking the hyperlink "What if I want to enter sales section totals instead?" the help sidebar says, "If you use sales section totals for your employee stock sales, you might report an inaccurate cost basis for your stock[...] Alternatively, you can adjust your total cost basis when you select Enter totals instead. You just have to add any missing cost basis to your total cost basis."
I don't understand mathematically how entering the total proceeds (from box 1d) and total cost basis (from box 1e) -- once per category of short-term vs. long-term etc. -- could possibly lead to an inaccurate cost basis. Nor do I understand the instruction of adding back in any "missing cost basis." It makes me worry that I'm not understanding something and that I actually have to make an adjustment, but I have no idea what that adjustment is.
