This is pretty much the definitive answer as far as I'm concerned:
I tried it on myself and I was offered way low then I expected - eventually, I was able to increase the offer by 5K, but that's it... I refused the offer. Of course there are other reasons - at least as they explained they had a limited budget (it was a startup...), and the latest negotiated value was 20% more than other people with similar responsibilities...
BUT, this was the startup... I guess with BigCo-s it is better to say your "BIG" number first.