Difference between Detailed Tables and Subject Tables


I'm new to using the census tables and had a question on the difference between the estimates given in the ACS subject tables and detailed tables.

For instance - I was looking at the Number of individuals that are below certain percentages of the poverty level for a given county

The 2019 ACS 1Yr detailed table estimates provide a total of 452k people where 5.9k are below the 50% poverty level:


The 2019 ACS 1Yr detailed table estimates provide a total of 1.8M people where 52.9k are below the 50% poverty level:


I have a feeling there's a hole in my understanding of what these tables provide or some unforeseen discrepency in the filters i'm using - but i'd like to understand why i'm seeing this discrepency -- and if what the difference is between the subject and detailed table, which one would you recommend for use?