In my essay "The worst project manager ever" I talk about some of these same flaws, but I also talk about the best project manager that I ever worked with, Sonia Bramwell, and I recount some of the lessons she taught me about great project management:

http://www.smashcompany.com/business/the-worst-project-manag...

About this:

>There is back-and-forth as the estimates are questioned for being too high, almost never for being too low.

Sonia did not allow us (the engineers) to talk to upper management, so she handled the translation herself. In some cases she was worried about macho engineers who competed on how fast they could do something:

"I can do that in a day"

"Oh yeah? Well, I can do that in 4 hours!"

"Ha! You two suck! I can do it in 2 hours!"

Perhaps Sonia's greatest ability was to figure out exactly how much each engineer tended to overestimate or underestimate tasks, and then to weight their answers accordingly. For the upper leadership, she was the only one who continuously offered accurate estimates of how long big new features would take.