If your Qlik Sense Application has the Excel file as your Data Source, yes, the charts will reflect the changes in your Excel file after you load your Qlik Sense Application.
If the Source of your Qlik Sense Application is the QVD file, then you will have to recreate the QVD file to load the changes on your Excel file and after that load again the Qlik Sense Application.
Every time you change your Data Source, you have to load again all the Qlik Sense Applications that depends on your Data Source, no matter what your Data Source - CSV files, Excel Files, Databases, etc.
