I am trying to develop a PM/maintenance cost for a multi-rooftop unit building comfort system installed on a stamping/welding facility. 3400 tons of Trane voyager RTU's, w/gas heat. Has anyone done this sort of calculation before? This facility is currently doing minimal maintenance, and I would like to be able to inform them what the "national average" per ton, per year typically is. Hate to see this multi-million $ system be destroyed due to lack of understanding...