Compressed Air Best Practices, Feb. 2017, by Tim Dugan.
http://www.airbestpractices.com/system-assessments/compressor-controls/compressed-air-system-commissioning-part-1-why-do-it

"“Retro-Commissioning” (ReCX) of compressed air systems has become a trendy activity with many utility demand-side-management programs emerging in the last 5-10 years.  This is intended to be the process of “tuning up” a compressed air system, getting low cost savings from mostly adjustments and repairs.  The term was borrowed from the building/HVAC industry, where it means to get a system operating as it was originally “commissioned”."