The best method to understand Cloud Service pricing is to look at the length for which Azure has allocated the resources for you rather than how those resources are used.
When you install a Cloud Service, Azure creates certain virtual machines (VMs) (resources) for you, and you are paid for the time these VMs are created.
This is more in line with the Consumption model, in which you are charged for the resources you (as an Azure customer) utilised rather than how your customers consumed the services that used those resources. This paradigm applies to the vast majority of Azure services.