Forgive me, I am not seeing where that filter is. On the left I click on "Reports". In the main window I have "Categories and Templates" or "Scheduled Reports" at the top to choose from. I select "Scheduled Reports" then at the bottom "Schedule Report" and inside that I am not seeing the choice you are showing.
I did try to add an "Access Group" of only that customer, however the report still gave me everyone.