You may have to have one value for each of the castle level (and may be upgrades too).

The castle and upgrade order:

"Fort, Fort, Fort, Keep, Keep, Keep, Castle, Castle, Castle,Citadel, Citadel, Citadel, Fortress, Fortress, Fortress"

so in the income generate column, you may have to have something like this:

"-100, -100, -100, -150, -150, -150, -200, -200, -200, -250, -250, -250, -300, -300, -300"

one set of 3 numbers for each level. The first number is for the castle, the other two are for the 2 available upgrades for each level. If upgrades doesn't cost more, then just make the number the same as the first number (as above).