Design Excel Staff Roster to work with MYOB payroll

We use MYOB for payroll. We use an excel spreadsheet for the weekly roster. We would like the weekly roster to automatically calculate the total hours worked by each staff member instead of doing it manually. There are different rates for different times of the days, so as well as an overall total hours worked, the excel spreadsheet must also calculate totals for each different time period. There are several different classes of employees. Each different class of employee has its own rate/times. Most employees hours change every week. An excel spreadsheet has previously been created to do this but it is too complicated. We just need the totals, not all the workings. This file is attached. It has two sections. The section Staff Roster works well but it is the computation section that needs to be refined into a much simpler format.