I am playing through XII again, because I know I had a lot more fun in the beginning of the game than later (having completed everything), and I was wondering about how characters gain LP passively when they are not part of your party (i.e., they are not in your party at all, actively or passively).

SPOILERS MAY ACCIDENTALLY OCCUR AFTER HERE

I mean, when Penelo joined my party for the second time, she came with a massive amount of LP, which allowed me to go pretty far on the board. Basch was the same way, along with Ashe. I am uncertain on when these last two gained so much LP, but I think Basch came with all of his after his actual joining of my party, rather than his guest appearance in Nalbina. Ashe's LP came, I believe, when I recieved her into my party in the Bahumaut. All three of these characters had over a thousand LP.

I figured that this was because the fact that my girlfriend and I spent so much time running around the Eastersands/Westersands after having these people either actually in my party (i.e., I could select them to be a part of my active party or I could de-select them and use which other characters I cared to) or as a guest (like Ashe when escaping the palace ambush). However, Balthier and Fran did not share in these extra rewards, despite them being a part of my party, leaving, and re-joining later. So I am confused.

Can anyone shine any light on this?