Extension of a buff tuning with a code element to update the

Hello everybody,


Since I have little knowledge of coding in S4S, I didn't know how to title the thread differently. Basically I just copy lines from other mods and hope for the best if I'm being honest. 

I'll just try to describe what I have in mind:

I have this buff tuning here:

<?xml version="1.0"?>

<I xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" c="Buff" s="10658919861899688676" i="buff" m="buffs.buff" n="Trait/3302277578">

<T n="buff_description">0x940EFDA9</T>

<T n="buff_name">0xFF3B5086</T>

<T n="icon">2f7d0004:00000000:ae52518f425b8a56</T>

<U n="game_effect_modifier">

<L n="_game_effect_modifiers">

<V t="continuous_statistic_modifier">

<U n="continuous_statistic_modifier">

<T n="statistic">16590</T>

<T n="modifier_value">-1</T>

</U>

</V>

</L>

</U>

<T n="mood_type">14640</T>

<T n="mood_weight">3</T>

<V n="_temporary_commodity_info" t="enabled">

<U n="enabled">

<T n="max_duration">8</T>

<L n="categories">

<E>Happy_Buffs</E>

</L>

</U>

</V>

</I>


This buff tuning changes the body of the SIM via the fit/bony slider.
But in order to see the change, the game has to be saved every time.
I would like to remedy this by implementing an automatic update in buff tuning.
But,  I just have absolutely no idea how to do it. 

I was able to find a line in a mod called GradualWeightChanges/GradualFitnessChanges that looked promising:


<T n="linked_stat">16590<!--commodity_Fitness_Fit--></T>


but simply copying them in didn't help.


Can someone help me with this problem? Is my plan even possible?

PLS help  

thanks