Sum data from a column in parent but ignore duplicate data

I have a client with a similar workflow for their field personnel.  We have them log in and out with what you would call a Dispatch.    That is a very different architecture than what you have built.

One potential solution is to remove the column with data from the time cards.   

Make a report variable that is the concatenation of the Tech name and total time.  Then group the report on that field.   Visually you will have what you are asking for.