I guess noone has found an answer for this in FS22 yet? Trying to do the same thing in my savegame tracker again ;D..
I've found the base crop prices in maps_fillTypes.xml, which a map mod can override if wanted (possibly linking to a differently named file). Here it also lists the base variations between the months. Starting from March sadly as that's the first period in FS22. So for instance 1.07 means that on average there's 7% higher prices than mean prices this month..
Then the save game has a separate set of definitions in careerSavegame.xml. As the months passes, it seems that the price for the period is then somehow randomly adjusted around that month, so the savegame's xml file will list the actual difference from the mean for this period in this specific year. I haven't calculated correctly the whole thing, so I can't be certain, but it looks like the multiplier in careerSavegame.xml replaces instead of adds onto the default periodic change, (but is a bit above or below due to some randomness function).
In the placeables definitions, you can find price adjustments for each selling station. I think they are mostly set to 1, but in the western wilds map I'm playing, the train station is for some reason set to a factor of 1.5, and thus you can sell goods there for +50% higher price, which always makes this the best selling station. This applies on top of the value above.
But then, the last factor (which looks to be a fairly small factor), is a small variation which is set per selling station. This is typically what makes different selling stations offer different prices, and likely explain differences within the same period. As explained above, the placeables.xml for the savegame will have data like:
Code: Select all
<stats fillType="OAT" received="0.000000" paid="0.000000" priceVersion="1" isInPlateau="false" nextPlateauNumber="1" plateauDuration="51840000" meanValue="0.000000" plateauTime="0.000000">
<curveBaseCurve nominalAmplitude="0.008858" nominalAmplitudeVariation="0.000886" amplitudeDistribution="2" nominalPeriod="172800000" nominalPeriodVariation="64800000" periodDistribution="1" amplitude="0.008619" period="73266584.000000" time="18415596.000000"/>
<curve1 nominalAmplitude="0.008858" nominalAmplitudeVariation="0.000886" amplitudeDistribution="1" nominalPeriod="604800000" nominalPeriodVariation="120960000" periodDistribution="1" amplitude="0.008835" period="502730496.000000" time="348835520.000000"/>
</stats>
I agree with the original poster that it's likely constants to adjust a function, and it sounds like two periodic functions combined. I haven't figured out the function either, though I haven't actually tried much, apart from trying to see if I could find something obvious. But an amplitude in such functions, is typically the maximum change from the mean value, and thus an amplitude of 0.008858 would mean that the prices vary less than 1% of the mean value, which is a fairly minor effect. I see some amplitudes getting a bit higher. It looks like products may have higher variations than raw products.
I've failed to figure out the formula the above inputs into. I guess it is unlikely to be documented anywhere public, as it's likely an internal development detail for a function in code to add some random variation between sellpoints. But with the period changes from the savegame and the selling station adjustment ratios, I at least get fairly close to the price.
