Poverty Universe difference between Supplemental and Official

I'm looking at the official poverty level and comparing to the supplemental poverty level using MDAT.  I understand the basic differences between the two measures.  I'm not fully understanding why there would be significant differences in the number of people "Not in Poverty Universe."  Any ideas?

UPDATE: actually, I might not be accessing the supplemental data properly.  I'm using the CPS Annual Social and Economic (March) Supplement (202303) with the "Perlis" variable.