This summary is intended to provide you with a better understanding of the fact that the plans that Microsoft has created are always based on the type and size of your organization.
It is possible to combine plans in the enterprise that fit your needs based on your experience of these kinds of products. However, it is advised that you contact a gold productivity partner to help you select which plans best fit your organization.
You can also see that the Office 365 service descriptions provide additional details about each plan. For more information you can refer to https://technet.microsoft.com/en-us/library/office-365-service-descriptions.aspx.