At last! Discotheque Of Doom ins running for me...

[brell]

This is very simple:

If you are logged in and then log in from a different IP while still logged in from the first one you'll have to update your session because otherwise the YaBB doesn't know which one to serve: The first or the second IP.

If you log off from the first IP and then you log in from a different IP you don't have to update your session because then the YaBB only sees you on one IP.

This has nothing to do with the

logged in for keeps

feature. I often logged both at home and at work and then I had to update my session. After I started logging off at home after each session I do not have to update my session when I log in at work.