Costing laboratory services is a huge job and takes a long time to do properly. I've done this many times, but only once from scratch and that one time took six months to finalize. The whole process depends on what the administration really wants and what you have to work with. There should be guidelines given and help forthcoming from the administration, as the results for the lab won't mean much if everyone does it a different way! I wouldn't even start figuring things until the administration gives guidelines and holds some meetings on how it is to be done.