Pub 551 essentially states the exact same thing as Pub 555 as far as I can see. There's no explicit reference to "equitable distribution" here and in any case the concept of equitable distribution also refers to assets owned by married couples.
In my experience brokers generally have a pretty good handle on basis issues, so perhaps they know something that you haven't disclosed here that, somehow, makes their reporting of basis correct?
IF you are absolutely sure that the basis of the securities you sold should be the FMV at DoD AND you are absolutely sure that the basis reported by the broker is wrong THEN I'd simply enter the 1099-B exactly as it reads and then use TurboTax's process, (a process that this year seems to be different between the desktop and online programs), to correct the difference. That will result in the sale(s) using the correct basis and the change from whats reported by the broker will be properly reported on Form 8949.
