You have to separate out:
- Boosts
- Town Skin
- VIP: Food Production
- Valley of the Aesir: Resource production
Get the sum of those and subtract it from the total Increased Food Production percentage.
Then you have it by the product of base production and those percentages.
This goes for all RSS variants.
Example:
P = Production Buildings = 185,000
I = Increased Food Production = 2,448%
Boosts etc.:
- Boost: Food Production = 100%
- Boost: Resource Production = 100%
- Town Skin: Resource Production = 5%
- VIP: Food Production = 60%
- Valley of the Aesir: Resource production = 40%
B = Boosts etc. = 305%
K = I - B = 2448 - 305 = 2143
Production
= P * (1 + B / 100) * (1 + K / 100)
= 185000 * (1 + 305 / 100) * (1 + 2143 / 100)
= 16805677.5
Rounded to:
16,805,678
Alternatively:
P * (B + 100) * (K + 100)
Production = -----------------------------------------
10000