It all boils down to they are the same engine and have the same power. As stated the over 10k trucks have the performance figures taken at a lower rpm to meet EPA requirements. They still have the same output at higher rpm.
Edit: I just noticed you had said F150. It could be for a bunch or reasons. Different exhaust or intake. Or it may be tuned higher as it has a lower duty cycle and is not expected to work as hard. The only way to find out for sure would be to see if Mike Anderson is still following the "talk to the 6.2 engineer" thread.