Even though you set custom quarters in settings, they are only used for reporting not other tool functionality. This is quite apparent when you are trying to use the Resource Management capabilities in Workfront. The quarters option only uses standard quarters.
This decreases the usability of this part of Workfront.
In addition, the way that an Admin has to maintain the list of custom quarters seems extremely manual. It would be better for Workfront to calculate what the custom quarters are based on "When does your fiscal calendar begin". If I enter February 1 then all of the quarters should shift accordingly and in turn both the reports and the Resource Planner.