In looking at the new POWPUMA delineations, I can no longer quantify how many people work in Seattle, but rather only the number of people who work and live in Seattle. There are many people who live outside city limits and work in Seattle. The PWCITY variable would allow me to do this analysis.
IPUMS-USA generates PWCITY based on POWPUMAs. This means that any 2012 ACS version of PWCITY would depend on the boundaries of the new Place of Work PUMAs. Because the new Place of Work PUMAs are county based (containing one or more complete counties), unless the city and county boundaries are identical or the county falls completely within City boundaries, it is impossible to determine whether or not a person works within the city or in part of the county containing the city. This makes it very unlikely that PWCITY will be created for the 2012 ACS sample.