I understand that they have to slit to either 16mm or 35mm. (super 8 is slit from 16 after perforating) and the slit film is not stored, and goes directly to the perforating room.
As I understand it, the entire production is one continuous set of connected systems. They set equipment up to confection/finish a particular product, feed all or a portion of a master roll in one end, and packaged product - whether motion picture or still film rolls - comes out the end. Perhaps with there being some straightforward transfer of intermediate products in the midst of the procedure.
That relative automation and inter-connectivity is critical to keeping prices at least within reach.
And the fact that they have nothing in that set of highly automated machinery that works for creating the 100 foot bulk rolls of still film is why Kodak branded bulk still film is relatively so expensive.