Metered License: How many credits operations takes

The problem is, that I don’t know how many credits the operations takes. “One ‘credit’ is counted each time you perform an open or a save operation on a document and you are billed for the total number of credits.” But this is not true. When I use Aspose.Tasks I do not make an open operation but it takes some credits even if I create a new instance of the Project class.
Can anyone explain that, please?

@marco.wittwer,
current logic (starting with release 20.9.1) can be found here.

We will update the documentation page Metered Licensing FAQ - Purchase - aspose.com.
Sorry for the confusion.