In case it helps, the line in the script that reads
is calling a procedure that the original Company of Dragons datafiles added to Herolab, and you should be able to view the script for that procedure with the editor to see exactly how it is getting or calculating the variables it uses.
Open the editor, and in the "General" tabs there is a "*Procedure" tab. Hit the "New Copy" button and choose the entry for "DracHero" in that list, and you will be able to read the script in the new copy you make.
You can't edit the original DracHero procedure used by the Company of Dragons data files, but sometimes it is helpful to see the code being used.