I-ford-
The qualifying statment to what you just quoted is:
"Maximum N1 represents the maximum rated thrust available from the engine. The EEC continuously computes maximum N1."
This statment precedes your quote:
"Maximum rated thrust is available in any phase of flight by moving the thrust levers to the full forward positions."
The Maximum N1,on a derated,assumed temperature take off would be the maximum thrust available with that derate and not the max un-derated thrust. So,if u advance TL's to full fwd position you still get only max derate thrust (which is what the EEC's have computed anyways and shows on your DU).
Cheers..