About your file, you cannot repeat the cost per hour for each worker because you're going to need to multiply all the hours of each person by his rate (cost/hour)....for all workers.
Yes, that is correct, but what is the problem with that?

Pedro, do yourself a favourite and keep all data in 1 sheet, and analyse the data with that sheet. (e.g. with a pivot table).

You did not answer my question, why the result is not the same.

Please reply.