Thanks FlyingStone, but the question was more related to the thrust rating given by the manufacturer. Using N1 was a mistake on my part.
The limits are based on % HP RPM in the document i am looking at, not N1.
Using the limits above, i take 100% HP RPM to be the design speed, and the speed used in the thrust rating measurements, with 104% HP RPM being the maximum available for a short time only.
Is this correct, or would the thrust figure published come from testing at maximum RPM?