Newbie Multifamily Question

[Creston Gerth]

I've been digging around the MLS just got get a feel for everything and looking at various different types of properties and areas. I came across a quad that's in a complex and wanted to research the sale history on our county assessor page. The MLS has it with the address and lists it as Unit C but the description says it's 4 units. When I pull the address on county assessor it lists 4 different units ( same addreas units A-D) with 4 different owners. Am I missing something here?