D800 "extended memory banks

In the D800 shooting menu there is an option to turn on or off "extended memory banks"
The description is the following:

The On setting includes exposure mode, shutter speed (S and M) and aperture (A and M) in the settings for each memory bank.

Can anyone tell me what this feature does? I know my SLR pretty good buyt this one has me baffled
Thanks for the help