I am looking for updated studies with cost data for LEED v4 Commissioning services, including Enhanced, Envelope and Monitoring-Based Commissioning.  "The Cost of LEED v4" is a good publication, but I am looking for more data focused on commissioning.  Most of the articles I find from PECI and other organizations are out-of-date.  Does anyone know of any good industry publications with commissioning fee data (percent of construction cost or $/SF) for LEED v4 projects?  Thank you.