Medicaid enrollment variables


Can anyone point me to documentation that explains how the allocation flags tie back to the primary variables? I'm specifically trying to get estimates of Medicaid enrollment by using HINS4, FHINS4C, and FHINS4P, and while it seems like the variable 'FHINS4C' is the coverage edit that Census created in 2009 to check eligibility for Medicaid, I can't find anything that describes 'FHINS4P'.  I also notice that there are 399,998 records marked '1' in FHINS4P (which would seem to indicate the person is enrolled in Medicaid) but are marked '2' in HINS4 (which would seem to indicate the person is not enrolled in Medicaid).

Thanks for any help.