The saved vars file
is lua source code.
It defines a global table when you load it, so you don't even have to parse it, you can simply use it the way it is.
Combined with the library mentioned in the linked SO answer, you can just load the saved vars file and write it to an excel file.
I know that your way works too, but the safest and easiest way to read a lua file will always be to load it in lua
