This depends on the logic. There are two possible approaches:
1. Use a custom color of the grid cells to indicate the allocated hours (from-to). You can use BeforeCellRender to set the color directly or you can set just the IsBusiness flag (then the default style for business hours will be used).
2. You can use an event to show the allocated hours (from-to). If you want to display both (allocated vs worked) you can use event versions: http://doc.daypilot.org/scheduler/event-versions/
Let me know if this isn't what you are looking for.