"This is because the THR HLD funtion is activated and the thrust lever motors are declutched."
Or, more accurately, the 744 thrust levers servomotor(singular) has it's electrical excitation removed. No physical(mechanical) declutching takes place
There have been several excellent postings on setting EPR before certain speeds on the PPRuNe (Try using the search keywords "setting EPR").
e.g.
http://www.pprune.org/forums/showthr...ht=setting+EPR
Regards.
Q.