You can do this by calculations and sorting and layout settings... or you can do it with relationships... or a combination.
At the end of a report you can have a "Trailing Grand Summary" part on the layout. It will allow you to place the totals fields at the end of your report in the layout which the PDF shows.
When you want a breakdown by Department or by Service you can use the existing summary field to show the totals by creating a relationship to the data by a calcluation field which has a value H relating to the Department. Using that relationship you can place the related summary field Dept H::total hours next to your H. You can create a new relationship for each of the other values.
And of course, if it's mission critical and you aren't able to figure things out, it might be worth it to find a consultant to help you out.
Elance.com and Odesk.com are good places to find some help.