We do, though: A standard Chosen takes away 1 Influence, a Superior takes away 2, Undead/Animalistic subtract 3, and Angel/Devils subtract 4. The code line that calculates the influence value of your next city is just this:
Code:
(w.nextCities[n]).influence = w.influence + baseGain + lowest - influencePenalty[n];
w.influence is your current influence
baseGain is a constant that was set to 10
lowest is the lowest among the two cities' influence penalties (just the sum of their species modifiers)
influencePenalty[n] is the influence penalty of this particular city (again, the sum of their species modifiers)
In a later line, the item is chosen and that value is subtracted from nextCities[n].influence. Another few lines handle the subtraction of any items gained by warping past an odd-numbered Loop.