National currency relative value

[Kombinita Socialisma Demokratio]

Does the inner workings of NationStates take into account GDP/GDP per capita as well as average income and average disposable income such that one can calculate a consistent currency conversion? Using NSDossier on my own nation, I see a conversion factor to and from international dollars, but this is still inconsistent. For once I convert NSDossier's report GDP per capita from international dollars to the national currency,it is not equal to the actual user-visible average disposable income. As I understand it, GDP per capita should equal average disposable income. Is the disparity due to a lack of true methods to convert national currencies, or what am I missing?

My apologies if Technical would have been better suited; I thought that this were better because my question is not about resolving a technical issue

[Comfed]

Average disposable income is, I believe, money not spent on essentials (therefore is "disposable" or "unneeded").

[Kombinita Socialisma Demokratio]

Average disposable income is, I believe, money not spent on essentials (therefore is "disposable" or "unneeded").

I thought that what you are describing was known as average discretionary income, and that average disposable income was average income * (1 - average tax rate).

[Comfed]

Average discretionary income is not a stat.

[Kombinita Socialisma Demokratio]

I know that discretionary income is not a stat, but considering the discrepancy between NSDossier's GDP per capita (in dollars) including their currency conversion factor and the average disposable income, is there a way to calculate consistently relative currency value?