On the subject of de-rates. The de-rate of the engine is selected on the FMC by the pilots from a choice of 22,24 or 26k lbs of thrust for each departure depending on runway & weather etc.
26k is the maximum on the 737-800 although most departures are made using 22k thrust and an "assumed temperature" correction is often added to bring the thrust down even further. All very common practice in the industry.
However even with full 26k thrust BHD's runway is still very limiting on payload for longer routes.