I am working my way through Gradus ad Parnassum (Mann translation). The chapter is: third species in three voices. At page 92, I see an example (Fig. 130) that ends like this:

I cannot understand the closing formula of the Counterpoint. It is 6M 4 5 6M from the Cantus Firmus, but earlier in the book (two voices) we were told that the closing formulas in third species (with Cantus Firmus on the lower part) were (p. 52):
- 8 7 5 6M or
- 3 4 5 6M
I feel I am missing something.