How early in the year did you import the data? Brokerages sometimes have incomplete or updated information available which will be reflected in the mailed 1099-B statements. I usually do not file unless I have that printed statemen in hand to agree the numbers to the imported data. And of course the brokerages do release corrected 1099-B statements from time to time, like 10-15% of the time in my experience. YMMV, but be careful filing with early brokerage report numbers if they make a significant difference in your tax liability.
