Fred58,
The short answer is Yes, TurboTax is permitted to round figures. These appear on IRS form 8949 "Sale and other Disposition of Assets". The instructions for that form (https://www.irs.gov/pub/irs-pdf/i8949.pdf) state on page 2:
Rounding Off to Whole Dollars
You can round off cents to whole dollars on Form 8949. If you do round to whole dollars, round all amounts. To round, drop cent amounts under 50 cents and increase cent amounts over 49 cents to the next dollar. For example, $1.49 becomes $1 and $1.50 becomes $2.
In fact, at least the last time I looked into it, IRS blessed software is required to round and report dollar figures.
If the 1099B total gain is less that what TurboTax computes, by all means be happy you are saving a few bucks. If it went the other way, you may be able to close the gap by reporting only 1099-B totals in TurboTax. This is available through one of the two Exceptions listed on page 3 of those instructions. Exception 2 is a bit onerous as you would essentially have to make an equivalent of 8949 showing the pennies and any adjustments and then attach it as a PDF or print it out and mail it separately using form 8453.
