The FAQ on ACS/PRCS multi-year files states
For some high-income cases, previously topocoded values are no longer topcoded.
Does this only apply to income variables? (Is there a comprehensive list of affected variables?)
(I compared property taxes in the 2009 5 yr ACS file to the single year files of the corresponding years but couldn’t find any observation which was not simultaneously topcoded in both sources.)
For IPUMS multi-year datasets, variables reporting dollar values have been inflated to dollars for the last data year resulting in top- and bottom- codes that differ from the single-year ACS documentation. This difference between the IPUMS 1-year files and IPUMS 5-year files applies to person-level and household-level dollar-value variables such as income variables (i.e. INCTOT and HHINCOME), housing and utility cost variables (i.e. RENTGRS and COSTELEC), and property tax variables (i.e. PROPTX99). Specific variables affected and their corresponding top- and bottom-codes can be found on this page outlining Top Coded and Bottom Coded Values for ACS/PRCS Samples by State.
Thanks a lot @Grace_Cooper !