If you have the time, could you please post a short but complete example of this sort of packing and unpacking? I have just looked at the Wiki page for the %JSONFromVariables% token but it makes little sense to me.
Pack the variables into JSON by changing Prefix given with the %JSONFromVariables%Prefix% token to the common prefix of the variables you want as JSON keys
Here's a bare minimum demo for packing, passing by parameter, and unpacking. Run "Main", enter your values, and "Submacro" will display them. I've set "Submacro" run async and started it with a pause to prove that, despite having the same names, these are being passed by parameter and aren't available through submacro "inheritance"...