DT12 settings, manual and auto performance disabled.

Because that's the way your company wants it set up as far as the auto performance.

The manual setting requires you to press & HOLD it in until it switches. Usually 3 or 4 seconds.
Or it could be the way the company wants it set up also.

 

Ours had econ and manual. 505s pulled pretty good in manual mode

 

Anyone with an ECM hookup could change the parameters but that would be considered tampering with the equipment which would probably lead to termination.
I suggest you talk to someone at your company and inquire about it. You never know, they may change some things