Ok I found out the 13.8 business with OEMs is only for the PPC units that could/will be OEM. Those will also do boost at about 14.5 IF battery voltage falls to say 12.6 or whatever. It is still being sorted out with OEMs as to just exactly what profile they want in their PPCs. The OEMs want "automatic" for their customers, but battery guys can still get their kicks from the adjustable voltage mode :)
The aftermarket deck mount models are different, with boost at approx. 14.5v depending on what you get. They also do the single adjustable voltage, so you can pick any voltage you like to meet your battery's spec.
Once things settle, manuals and websites will get tidied up.