The Carrier internally geared centrifugal compressors (17 Series) use a hydraulic oil in the compressor, essentially the same as Mobil DTE heavy medium. They need the antiwear additive package to protect the gears. This is one of the few compressor models that use this type of additive package, but there are a lot of these compressors installed across the globe. Oil test results for these systems get flagged incorrectly by test labs all the time.
I am not aware of any public information on refrigeration oil testing limits. The ASHRAE 2002 Refrigeration handbook chapters on lubricants, system chemistry, and contamination control have some basic information on the fluids used in the refrigeration system.
I learned my craft by working for a lubricant and refrigerant manufacturer where I was responsible for helping the system and compressor OEMs transition away from CFCs into the replacement refrigerants and lubricants. I worked with OEMs doing life testing and field trials on systems and analyzing the fluids and components coming out of the testing. Many of the limits used in the industry are based on these type of test results, as well as historical field failures and system chemisty knowledge of the particular fluids.
Your moisture limit of 100 ppm is too general for me, but may be acceptable if you restrict it to HCFC and HFC refrigerant systems. My limits are based on the particular refrigerant / lubricant combination, compressor type, and application temperature. For the system PT described, I would use a 35 ppm limit for moisture because the CFC-11 refrigerant in the system is relatively unstable around moisture and will lead to strong acid formation.
Organizations like ASHRAE and RSES are where the people plugged into the refrigeration industry gather, and only two lubricant test labs regularly participate. There are a couple of other test labs who know one manufacturer's systems well because they do a lot of work directly for them (likely the case with your lab), but none of them have a broad background with multiple manufacturer's systems. Some customers have developed the expertise to interpret the test results on their own, but if something out of the ordinary comes up they are usually lost because they don't know the system chemistry well enough.