Today I was testing this function further and I think it is a little bit buggy.
The first kit is imported as I described. The second kit too, with samples going from 13 to 24.
Bug description: However, if I save the project and reload it, the second kit doesn’t find its samples because it then searches for them in the original sample slots. 
This is a little bit strange because directly after copying the the kit, it works. 
Edit: (solution, hopefully)
- directly after pasting and loading the copied kit in the new project,
- I altered the kit minimally and
- saved it again.
- Result: seems like everything stays put when reloading the project then
