So you know what is the symetry, and you said you didn’t understand where was the symetry. This is inconsistant…
Without knowing maths you cannot do that, and it’s not interesting too without considering the old values exchanged + the creation of ğvalues the individual make between t and t+1.
The money function which is a partial view of the economical exchange will be a function f(d,x,T) where “d” is the amount before exchange, “x” the number of money exchanged, and “T” the period of time considered without any more change, with T << ev, because man is not eternal.
@Sofrani made yet some calculations to think about money properties, ask him to evaluate this function for you, and then make a Libre Office Calc with Money, Old Values exchanges, Creation of Values all between t and t+T with T << ev, to make a full example of what you are “thinking” about…