I guess I have been using the Engine Techs upgrade card incorrectly. Up until now I have been using it anytime I maneuvered. However the effect starts out with the symbol for the <Maneuver Command>: According to page 5 of the Rules Reference that would mean that you can only activate that upgrade when you either spend a Maneuver Command Dial or a Maneuver Command Token.

I believe that the above is correct, if I am mistaken please correct me.

You are correct. You must resolve a Navigate Command. Which is indeed, either a Dial, A Token, or Both.

I think of it this way:

Engine Techs sit on their butts and/or do maintenance work until such time as they're given orders to the contrary... 90% of the time when your ship is maneuvering about, they're still not doing anything, because they've already set their switches, and you're just commanding the Helm to Navigate...

But throw a Navigate order in there, and the Engine Room is on Standby to - at the very least - Speed up and/or Slow Down... Or have the engines feathering to increase yaw rate, etc... This wakes up those additional engine techs - so they're good to go.

Great officer to put on a GSD with engine techs is Wulf Yularen (sp?), if you are playing Imperials that is. Bank a navigate token on first turn, then when you spend that nav token later on, you can exhaust Wulf and he will bring the token back. So you can always use engine techs (granted, someone isnt using the upgrade that gets rid of tokens).