When the PF calls for Gear Down and Flaps 15, is it a standard response to do ANYthing with the condition lever? If so, what would you expect the PNF to have done with the condition levers at that time. Apparently, "levers to max" is a woefully inappropriate choice at that time. Once made and trouble develops, should there have been a thought of "oops, whatever I just did may have caused this I should think about hitting that "undo" button"?
Condition levers to max is quite normal at that stage.
The 400 is obviously a little different in how the condition levers work compared to the smaller Dashes, but the procedure in the smaller aircraft is pretty much how it happened in the accident (without the accident part of course.) Gear is selected down, flaps to 15, and condition levers to max. As the condition levers go to max the torque drops right off and the pilot flying will need to compensate with an increase in power.
Power changes when leveling off, rudder trim changes with airspeed and power changes, power changes with configuration changes, even with all automatics engaged, the Dash 8 must be flown at all times.