I have a requirement wherein the incremental load has to be implemented by assigning the script to a variable and the variables are to be used in the place of the script in Edit Script dialog. That is only the declared variables are to be used in the edit script dialog instead of the actual script, so that whenever the tables and its field names are to be changed, we can change it in the declared variables and need not change in the script dialog window.
Are your variables used only for the incremental loading? such as to hold the max row of the last reload?
If so you can play around with the dollar sign expansion such as $(MyVariable) or with single quotes '$(MyVariable)' so QV treats this as a string in the script.