I will take a look at that shortly.
As for 7-Zip multi-part files, a portion of what is done involves compression, but most importantly, the other part is capping max size of file segments at 200 MB (200000000 KB).
When 7-Zip segments the file(s) to be packaged in a multi-part ZIP, one file will have a non-zip file extension, and the segments will have numbers in their file names.
One ends up with multiple files, which which when de-archived (only using 7-Zip itself), reassemble the original file(s) / folder(s).
This is not a process intended to use 7-Zip to compress a single file into a single Zip; rather, this both compresses and segments original files into multiple special 7-Zip format, output and transfer files.
Anyway, I'll access the above ZIP shortly.
GaryGB