Upgrade Market to Rice Exchange? An objective analysis

[Maltz]

Now we can make some charts! (And they are now updated to remove errors and improve accuracy!)

But since there are two many variables, we have to fix the others and only examine one or two at a time.
First, let's look at the effect of number of provinces.
We will reasonably assume the following:

Base Tax Rate (BT%) = 30%
Number of Provinces (P) = 22, 16, 10
Number of Turns (T) = 1 to 100

With Good Metsuke:
Effective Tax Rate (ET%) = 32% (22 provinces), 34% (16 provinces), 36% (10 provinces)
Average Effective Tax Rate (ET-AVE%) = 20% (22 provinces), 22% (16 provinces), 24% (10 provinces)
Reduction of Sum of Town Growth from Base Tax Rate (RS) = 0.26



Chart 1 - Metsuke in the Province

The precense of Metsuke boosts the income of the province in which he is stationed.

Let's take the green line (16 provinces) for discussion. The initial deficit of 1500 (the cost of the Rice Exchange building) will slowly pay off. At about turn 17, the Rice Exchange option breaks even with the no upgrade option (which means they make the same amount of money).

From then on, they earn more profit over Market alone, but this extra from Rice Exchange max off at turn 58 or so at about 1400 koku (which is not a lot, really), and slowly head to deficit that goes deeper and deepr due to the loss of long-term town growth. After turn 95 or so, Rice Exchange actually makes less money than market alone. We still make money, just not as much as if we leave Market in the basic form.

As we have more provinces (the red line), the benefit of town growth is more pronounced. At 22 provinces (the magic number to pause before Realm Divide on Domination campaign), the extra profit of the Rice Exchange is only positive between turn 20 and 60, and the extra profit is just several hundred koku at best.

But if we have less provinces (the orange line, 10 provinces), upgrading to Rice Exchange sounds like a great idea when we put a good Metsuke there. The extra profit beats the alternative for a long time. However, by staying small, we already lose income from collecting less tax from additional provinces in the first place. So why would we purposely stay small?