So far, they evolved like this for me:
Valentina (R)
Valentina + (R+)
Valentina ++ (R++)
Valentina +3 (R+3)
Valentina +4 (R+4)
Chocolatier Valentina (HR)
Chocolatier Valentina + (HR+)
And that's how far I've got
So, thats why you need 6 Valentinas to make a Chocolatier Valentina.
And you can upgrade the HR version with the R version, thats why you "only" need 11 for the next step