Rumbling GTA

A friend of mine is putting a Powerglide transmission into his Camaro. He told me he's considering the B&M Pro Bandit shifter for the application, where my curiousity led me to read up on the shifter to better understand it. Everything was clear to me until I read on how to operate it. Based on B&M's manual, starting from the shifter all the way back, there is low gear, high gear, neutral for "driving around purposes" and a true neutral. I figured that true neutral is the regular neutral, but am confused as to what is meant by neutral for driving around purposes. Can someone help shine some light on this for me. Thanks in advance.