407,
Exactly, the different power/temp ratings carry different lives, with the higher power leading to shorter lives, generally, but not always.
The method of calculating the life is an art, and each agency has a spin on that art. For example, if the exact same engine is tested to US Navy requirements it will have a given power for its overhaul life. If it is tested to FAA/JAA requirements it will have almost 10% more power for the same life. Why? Because the test sequence for the Navy has many more presumed cycles at high power than does the FAA sequence so the Navy engine has to go to its high power often enough to require that power to be less than the FAA will allow, if full life is to be achieved. We call the sequence the "spectrum" and it is the biggest driver for the determination of power and life.
The funny thing is that we now have the tools to measure exactly what the engine truly experiences, so we don't have to guess at a "spectrum" any more, we just have to measure the real life experience, and dock the remaining life accordingly - except that regulatory agencies have no idea how to deal with this new technology, so they just ignore it (so far.)