Shelter and the CPI, a Mistake?

Economic Disconnect has pointed out what looks to be a glaring error.

He points out the problem as seen here.

It may just be part of the annual recalculation of the seasonally adjusted indexes throwing things off, but even then it looks like a mistake. There's nothing quite like adjustments to adjustments to muddy the picture.

BLS: CPI

UPDATED Each year with the release of the January CPI, seasonal adjustment factors are recalculated to reflect price movements from the just-completed calendar year. This routine annual recalculation may result in revisions to seasonally adjusted indexes for the previous 5 years. BLS made available recalculated seasonally adjusted indexes, as well as recalculated seasonal adjustment factors, for the period January 2005 through December 2009, on Wednesday, February 17, 2010.

Let's look at the raw nonseasonal data and see how accurate it appears. That's all that really matters to those of us tied to the CPI (say investors of TIPS). We are not paid based on seasonally adjusted data. We are paid based on the raw data.

The data can be found here.

Shelter: 247.863 to 247.950

Shelter is composed of the following 4 items.

Rent of Primary Residence: 248.999 to 249.144
Lodging Away from Home: 122.638 to 125.778
Owners' Equivalent Rent: 256.727 to 256.591
Tenants' and household insurance: 123.812 to 124.360

247.863 * ((249.144/248.999)*5.966 + (125.778/122.638)*0.769 + (256.591/256.727)*25.206 + (124.360/123.812)*0.347) / 32.289 = 247.942

That's within the rounding error of the 247.950 that's claimed. At least that data seems consistent.