Yes, the expanded-data index includes purchase-money mortgages from other sources.
The approach to estimating the expanded-data HPI is detailed in the Highlights article published with the 2011Q2 HPI at http://go.usa.gov/8kNm. In general, the methodology is the same as is used in the construction of the standard purchase-only HPI, except a supplemented dataset is used for estimation. The augmented data include sales price information from Fannie Mae and Freddie Mac mortgages as well as two new information sources: (1) transactions records for houses with mortgages endorsed by FHA and (2) county recorder data licensed from CoreLogic. The licensed county recorder data do not include records in many U.S. counties-particularly rural ones. To ensure that the addition of the CoreLogic data to the estimation sample does not unduly bias index estimates toward price trends in urban areas, the expanded-data index for certain states is estimated by weighting price trends in areas with CoreLogic coverage and other areas. Details on this sub-area weighting can be found in the text of the Highlights piece referenced above.