Just a note on the 68RFE. The Auto-6 (the plus/minus buttons) controls the HIGHEST gear the trans will go to. It will still shift up and down, but will only shift up to and including the gear shown in the display. IOW, if you set it to show 4, then the trans will shift through 1st, 2nd, 3rd, AND 4th as required by current driving requirements. Also, the number in the display is NOT the current gear, it is the HIGHEST gear allowed. If you want to see what gear the trans is currently in, you will need something like an Edge Insight (at least on the 08MY, don't know about newer trucks with the info screen).
The Mad Norsky, if you are shifting into Auto-6 mode, what you are seeing then is the Auto-6 limiting to the highest gear you are currently in. So, if you are at a stop, then it will go directly to 1st. If you are cruising in 5th, that's what will display. The trans will still shift into gears below what is displayed as required. Again, my experience is from my 08MY, but I suspect newer ones will be similar.
As for selecting gears, I do it all the time, usually without even looking at the shifter (or display many times), even while moving. But then, I always use the Auto-6, except when using tow/haul, and even then I often engage Auto-6 mode. It allow me more control over the trans, and to a point to play "big-rig" ;).
Cheers!
Mike