It appears the whole maintenance thing is totally screwy at the moment. I am no expert, but it seems to me that the problem has arisen due to the new home and overseas cities thing which I think is new here. What appears to be happening is that the the base totals are wrong and that home cities are being counted as overseas and vice versa.
For the base totals, it seems that the maintenance costs are by default 0% and city maintenance is, for the most part, utterly meaningless now. You can get around this by increasing the HomeAreaMaintenanceModifier and OtherAreaMaintenanceModifier by 100 points for each of the Government civics. This restores the maintenance costs to more or less how they should be.
However, the switched home/overseas values mean that something like Conscription is also causing problems as it actually increases the maintenance of all your home cities by 25% and it means that you are not getting free maintenance with Chiefdom. I guess you could change all these too. But then again, Despotism seems all wrong and I can't seem to get that to work as it should be.
Really, it would be nice if Afforess could have a quick look at this as he presumably knows more about what is going on here and can (hopefully) put in a simple fix. Otherwise, I think the 1.76 mod as it stands is completely broken, which is a shame.