what does rebenchmarking mean?

As I understand it...the weekly numbers are basically just a guess. They call people up and ask "How much do you have?"

Geko45 at Peakoil.com explained it this way:

The weekly report is compiled from a survey of a subset of the industry. As such, it is subject to a margin of error (as are all surveys). I do know that once a quarter they attempt a more in depth "recalibration" to try and ensure they don't drift to far from reality.