Current company uses min (determined by EFB ) take-off thrust possible, often DeRate 2 (22k from a 27k engine) & max assumed temp , + improved climb, so take-off N1 = something close to high idle
However. . .this is purely to preserve engine life & apparently power setting after airborne has no detrimental effect on eng life. So given the most economical in fuel burn is to use full climb thrust (if continous climb expected) to shorten time in climb , it goes like this. . . . . . .
Take off at derate 2/55c or whatever . . 800' full climb thrust
indeed feels odd, but that is what they want us to do.