I have never played this game

[Edge7]

Note: if unit X has 'Gained JP-UP', the extra JP given by that
ability are ignored in the JP sharing equation.

Well, that clarifies that.

Also, the way I've always viewed the Ivalice games was that Final Fantasy XII takes place in Ivalice's Golden Age, and that Final Fantasy Tactics took place in its Dark Age and Vagrant Story is either around the same time as FFT, or it takes place shortly before Ivalice's Age of Enlightenment (which is more my own theorizing rather than it being based on any actual concrete evidence. It just struck me as taking place in an era equivalent to the Renaissance).