Also, one note on the power reduction and then increase on the United manual - the reduction is for noise abatement and cooling. Until the plane gets "cleaned up" where they can accelerate, the power reduction serves to slightly reduce the noise for people on the departure path (UAL flew out of airports that even then were very heavily built-up around) and not put as much heat in to the engines at low altitude while the flaps and gear were retracted. They also leveled off during this climb segment, so it's not like they were getting behind the power curve. Once the gear and flaps were up, power was advanced and climb resumed.
Thanks for the explanation. It struck me as somewhat strange that their lowest power setting of the departure sequence would coincide with the time that they are also the slowest, lowest, and dirtiest.