Cost and benefit plans are not copied over from the template when a project is created from a template. This could also happen when performing a XOG write action of a project into the application using a Project Template.
When you create a Project 'New From Template', you may encounter the following alert:
ALERT:Cost plans not copied because active fiscal periods could not be found for one or more start periods or end periods
Expected Result: Cost Plan from Project Template is copied successfully
Actual Result: Alert message is displayed and Cost Plan is not copied
Reference: Project Fields Used for Copying Financial Plans for an explanation on how the dates shift in the cost plan based on the new project dates and the overall functionality when copying cost plans from a template.