"OFF" means that the traction control and stability control are disabled (shut off).
In "SPORT" mode, TC and stability control are still enabled, but don't intervene as readily. The table referred to is on page 217.
Originally Posted by 2012 Owner Manual pgs 217 - 218
AdvanceTrac_ Sport Mode (if equipped)
The AdvanceTrac_ system provides an available sport mode on some models. This can be selected utilizing the stability off button as shown in the table above. Sport mode is not intended for use on public roadways as this mode provides less AdvanceTrac_ system intervention than when the default ESC and traction control systems are on. Sport mode will allow more spirited driving while the AdvanceTrac_ system is still enabled.
'08 GT coupe, 5M, wheels, tires, pads, fluid, a few suspension mods . . . finally lowered (all of half an inch)
'10 Legacy 2.5GT, 6M (hers) . . . '01 Maxima 20AE, 5M (spare, winter driver)