Write an instruction like
A #XS_Status.Bool1
and save, then you will see that the code size increases by 42 bytes.
"MC7" is the pure code size of the instructions ("machine code S7").
"Work Memory Requirement" is the memory requirement of the block with a block header or frame for managing the block in the working memory (for dynamic loading and deleting of the block). I guess the header/frame size is 36 or 38 bytes (check: save an empty block without code).
PS: Would it make sense if you post further questions
in your own thread?