Hi,
d00df00d - Some answers for you
The elemental analysis is done via ICP to a more accurate variation/version of ASTM5185
I have requested that my UOA schedule be varied to include viscosity at 100C and TBN again. It means little to me but may be more interesting for BITOG Members
When having the lubricant checked in the Oil Companys own Labs the structure of the lubricant is evaluated against their own data including programmed individual lubricant parameters. This makes for greater accuracy especially regarding the additive levels and their "exception" levels. I always advise them the version of the lubricant I'm using
Bear in mind that Mobil and Castrol Labs operate to very strict Quality guidelines