These two items have bothered me mightily for a long time.

First, in regard to total liquids, I never thought it made much sense.  I always thought that the crude + condensate numbers make a lot more sense, primarily because large volumes of NGL's come from natural gas reservoirs (also true for condensates, but less of a factor).    Also, you get distortions from refinery gains, especially here in the US.

Second, in regard to crude oil inventory numbers, they don't differentiate on the basis of quality.  A barrel of very heavy, less than 20 Degree API gravity, crude with a high sulfur content is counted the same as a barrel of 40 Degree API gravity light, sweet crude.   As Matt Simmons said, it's like counting a rusted out 1960 Plymouth the same as a 2005 Rolls Royce.  I think that it is quite likely--especially in light of the spread between heavy, sour and light, sweet crude--that growing inventories of heavy, sour are obscuring flat to falling inventories of light, sweet crude.