FX6 Menu - Tally?

[JoeCD4]

Hello all,
Scratching my head on this one.
There is an item in the FX6 "Monitoring>Display On - Off" menu section (5-4) that turns the "Tally" function on/off.
What is "Tally" in this context?
"Play/Rec Status" seems to control the recording indicator in the viewfinder.
Physical tally lights are controlled in a different menu section.
The operating manual gives no explanation and I don't see anything change in the VF when I toggle this setting.

Thanks for any insight!
~joe