Let me check if I got it wright (although not operating the NG):
A) Company pays for a 27k bump engine with 22k 24k 26k derates.
1. Takeoff at fixed derate 22K. Firewall, what do you get?
22k only, because of the FADEC.
2. Takeoff at 24K assumed temp. Firewall, what do you get?
27K - or slightly less if the FADEC thinks it's very hot.
B) Company pays for a 24K engine. Takeoff at 22k assumed temp. Firewall, what do you get?
24k.
Waiting to be shot down...