In Occupation Area, what does Aggregation by NAICS code do?

Good afternoon,

I've been examining occupational data for various US counties in the "Occupation Area" section of the Data Library dashboard.  There are three options under "aggregation:" 

I can tell that selecting either 2-digit or 3-digit NAICS code industries filters out a significant amount occupations from the results.  For example, if I have the Occupation Level set to "5- Detail," I pull 802 occupations for Butte County, CA, if aggregation is set to "unfiltered."  If I set the aggregation to "2-digit NAICS 546," and set the Industry filter to "61- Educational Services," I pull 406 occupations.  Clearly, this filters many occupations, and I can verify that many of the remaining occupations are related to Education.  However, the filtered list also includes occupations such as security guards and sheet metal workers, which certainly don't seem to be Educational Services occupations.

Is there a resource I could read to help explain how this filter works?  Is this filter returning all occupations in the region's data associated with employers within that NAICS code, even if those employees do not fall into an education-related SOC code?  If so, how can I confirm how IMPLAN synthesizes that data out of BLS data?

Best regards,
Donald Planey