Thank you for the guidance that adjusted cost should be entered AT THE TIME THE 1099-B information is entered... It is a quite concerning that the help box says we'll come back to that later - and indeed, TURBOTAX DOES NOT COME BACK TO THIS ENTRY AREA. As feedback - the Turboxtax program itself should notate this (your Cost basis was imported as a zero) and IMMEDIATELY instruct the user to locate the supplemental data (in the same document packet as the 1099-B) to make the appropriate changes...
In my situation, I noticed this - and felt it was not correct. After consulting 2 tax/finance professionals, a financial advisor, AND the brokerage account that sent the 1099-B with the Cost basis as a zero - they had all indicated that I should enter the cost basis.
