Just a thought (and sort of a message to Blackstone) but have you ever considered adding Sulphur to the list of things you quote on your VOA/UOA reports? If, as I suspect, you are running these oils through ICP, then you should get the answer for 'free' so why not report it?
Sulphur is one of those important elements that formulators always look out for, for all sorts of reasons. You obviously get it from ZDDP. You get it from sulphonates and phenates and other additives. You can get it from base oil (maybe not so much these days in the US but elsewhere in the world, definitely). Also sulphur is the 'S' in SAP so it's important to know what the number is from that perspective.