The item category is the customizing object that controls the billing of sales order items for a customer project. The item category is a parameter that defines the basic characteristics and functions of a sales order item, such as whether it is relevant for billing or not, whether it requires a delivery or not, and whether it can be invoiced individually or collectively. The item category also determines which billing plan type can be used for a sales order item. The billing plan type is a parameter that defines how billing dates are determined and how billing amounts are calculated for a sales order item. Reference:https://help.sap.com/doc/0f069b2e08b748f1b480d4c8b46c3c49/100/en-US/6a7a9f0a6e421014e10000000a174cb4.html

To schedule a project that must be finished at a given due date, you should use backward scheduling. Backward scheduling is a type of scheduling that calculates the dates of project objects, such as WBS elements and networks, based on their dependencies and constraints, starting from a fixed end date and working backwards. Backward scheduling ensures that the project is completed by the due date and that any delays are identified as early as possible. Reference:https://help.sap.com/doc/0f069b2e08b748f1b480d4c8b46c3c49/100/en-US/6a7a9f0a6e421014e10000000a174cb4.html

The reason why the cost element report for planned revenues does not show any revenues at all is that the manual hierarchical revenue planning has no reference to cost elements. Manual hierarchical revenue planning is a type of revenue planning that allows you to plan revenues for WBS elements manually without using sales documents. Manual hierarchical revenue planning does not use cost elements as a basis for planning, but uses revenue elements instead. Revenue elements are a set of data that define the characteristics and properties of a revenue type. Cost element reports can only display data that is based on cost elements, not revenue elements. Reference:https://help.sap.com/doc/0f069b2e08b748f1b480d4c8b46c3c49/100/en-US/6a7a9f0a6e421014e10000000a174cb4.html

Settlement, progress analysis, and results analysis are some of the functions available for period end closing in SAP Project System. Settlement is used to allocate the costs andrevenues in projects or the results analysis data to one or more receivers, such as cost centers, profitability segments, or assets. Progress analysis is used to determine and compare the planned and actual project progress values, based on the overall planned costs and the work done. Results analysis is used to perform a periodic valuation of the project, based on the costs and revenues expected or incurred in the project. Reference:https://help.sap.com/doc/0f069b2e08b748f1b480d4c8b46c3c49/100/en-US/6a7a9f0a6e421014e10000000a174cb4.html

Sales order and billing are some of the sales documents that can update planned revenues on WBS elements. Sales order is a document that records a customer’s request for goods or services from a sales organization. Billing is a document that records the delivery of goods or services to a customer and requests payment for them. Both sales order and billing can update planned revenues on WBS elements if they are assigned to them directly or indirectly via network activities. Reference:https://help.sap.com/doc/0f069b2e08b748f1b480d4c8b46c3c49/100/en-US/6a7a9f0a6e421014e10000000a174cb4.html