But it is for the 'business concept', and not for changing code customers are paying. Code is already written, it is just a matter for switch-on and switch-off

But it is for the 'business concept', and not for changing code customers are paying. Code is already written, it is just a matter for switch-on and switch-off ... which is again max. 3 minutes job. How many times companies sell same product? They are not rewriting the code, just sending you a copy - zero effort