It's an interesting one, and would replace the 2d6 roll every year I suppose. I won't add it in but feel free to give it a go and see if it works for you?
I'd try to set it up as follows:
The service income gets the 2d6 roll, but you lose all unspent service income at the end of each quarter. So using the existing sheet, on a 2d6 roll of 9 the Heavy Urban gets 9.6M C-Bills per year. Converting this to Service Income would change it to 2.4M C-Bills per quarter, but if you can't defend whatever is being built with that Income then you lose all of it. So if you were building a project costing 5M C-Bills, had managed to keep the location safe for 2 quarters (4.8M C-Bills spent so far), then a raider gets in during the third quarter (where you were spending the last 200k C-Bills) and damages a key item on the map, then the entire 5M C-Bill project is lost.
For actual income, you would only get half the 2d6 roll. So the Heavy Urban would only produce 4.8M per year as money in your pocket.
You do get 50% more income, but 2/3 of your income can only be used for local projects, instead of being used to hire off-world experts to help uplift your steading, or pay for salaries for mercenaries, or purchase additional weaponry/armor/equipment. You also take the risk that if a Raider gets in during a Quarter to destroy the on-map MacGuffin, then all the Service income for that Quarter is lost.
One note on the Noble Ruleset tab is that cell B77 says that Maintenance Cost is 1/10 the purchase cost, but cells F83:F90 have the Maintenance calculated by taking the Purchase cost and dividing by 100.
Another way to start would be to change the 2d6 chart on the 'Noble Ruleset' tab, cells D58:D68 to the following:
2 - Badlands
3 - Wetlands
4 - Badlands
5 - Hills
6 - Mountains
7 - Wetlands
8 - Wooded
9 - Coastal
10 - Flatlands
11 - Light Urban
12 - Heavy Urban
Then state that during the start (cell B51), you roll 2d6-2, with any result less than 2 treated as 2.
So when starting out, the percentages of getting the terrain types is:
Badlands - 30.56%
Coastal - 5.56%
Flatlands - 2.78%
Hills - 16.67%
Mountains - 13.89%
Wetlands - 22.22%
Wooded - 8.33%
The least valuable land is the most likely to be allocated to a new noble, and the extremely valuable Flatlands are the least likely to be allocated. So the player gets plenty of land to work on, and potentially the GM can allow the player to convert some of the terrain (i.e. spending lots of money to convert Badlands to Wooded terrain for a 3* income boost) Mountains might be worked on by MinerMechs to be converted into Hills (+50% income boost)
For regular 2d6 rolls, the results are as follows:
Badlands - 11.11%
Coastal - 11.11%
Flatlands - 8.33%
Hills - 11.11%
Mountains - 13.89%
Urban, Heavy - 2.78%
Urban, Light - 5.56%
Wetlands - 22.22%
Wooded - 13.89%
Here the Mountains, Wetlands, and Wooded terrain is the most likely to be acquired. Not sure how that would affect the game.
