Yeah, I interpreted it as such, which made me even more confused there's only milk and no other dairy products. Here in Germany at least, if protein for cheap is what you want, you go with Quark or Harzer.

EDIT: Huh, I just did some very rough math in my head, going with 1,35€ for a 500g pack of Quark from Lidl, and interestingly, that seems to put it roughly at the same place as actual milk, with it having 60g of protein, that is fascinating.