shit reading all of that made my head hurt lol
13speed is jsut like a 10speed except u can split the gears
What i do most of the time (less than 32000lbs) is I shift just like a 10speed till i get to "10th" gear then i push the red button up and let off the gas and go back on the gas the truck will shift
The other way to drive a 13speed is to go 1-4 go flip the selector and go into 5 now to shift into 6 press the red button foward let off fuel go back on fuel truck will shift to go into seventh press the red button back and move the shifter repeat steps to shit rest of gears.
Hope that helps
if not probilly just got u all turned around!!