Calculation of Production Income?

[AKronblad]

I know that the version of production income calculation (from 1.12.2, and yes this is from a mod) may be or even is obsolete, but I still someone has the history and knowledge about older versions for this topic to be able to explain to me how the numbers are derived, because I simply cannot reconcile them.

How do the different modifiers (-12.5%, -75%, -62.8%, +25%, +5%, and -5%) produce the -36.8% Production Efficiency?

 

[AKronblad]

I believe that I figured it (or something likely) out myself:

Production Efficiency from Country Modifiers can never fall below +1% (Tribal Heritage: -12.5%, Fully Delegated Authority: -75%, summing up to -87.5%, but with a floor of +1%..)

However, the Production Modifiers (the rest, summing up to -37.8%) can bring Production Efficiency into the negatives: +1% + (-37.8%) = -36.8%.

Makes sense?