It does indeed mean a difference on which year and emission equipment is on the engine. Mine is EGR equipped but no DPF. As the EPA mandated more junk on these engines, the soot loading has increased and, as WreckerMan stated, the after treatment devices demand certain things from the oil as well.
Heck, if in doubt which oil to use, then call your local Cummins shop (not a vehicle dealer) and give them the engine ID number and they will give you all the information you need.