On that last chart Jane, how much you'd have to do depends on each factions starting inf, so...
Example 1: A faction at 11 % inf has a commander put in 10 pts of inf (~90 effective). For that to be countered by a commander whose faction is at 21% (about 60 effective), you'd have to do ~ 90-60 = 30 pts, about 50% more work, so 1.5*10= 15 pts of inf.
Example 2: Likewise, A faction at 41 % inf has a commander put in 10 pts of inf (~20 effective). For that to be countered by a commander whose faction is at 11% (about 90 effective), you'd only have to do ~ 20-90 = 70 --> 20/70=~30 %, so 0.3*10 = 3 pts of inf.
The actual effect in both cases would be seen as both factions gaining the same amount of inf, as all other factions fall by some relative amount, based on their starting inf.
Is that using the chart right?
I could see how this would help if you are alone in a system trying to manage multiple factions' movement.