Since I am not really experienced at scoring for orchestra, I thought I would embark on an exercise to help me learn more about both orchestration and Notion. So I started a project to "Notion-ize" Rachmaninoff's Piano Concerto No. 2, Opus 18. I figured if I could complete that project I would learn most anything I needed to about Notion.
So I started, and things are going OK. It's been fun. But I'm running into an issue with the Horns. While other instruments that sound at a different pitch than written in the score work fine (Bb Clarinet, Viola), the Horns (Corni) are off pitch. I read online that Horns should sound a perfect fifth below the note on the written score, and the Staff setting for the Horns in Notion says:
Notated C sounds:
F, Same Octave, Lower
So I can't figure out why the notes written on Rachmaninoff's score for the Horns (only) sound dissonant and clearly are either written wrong (I doubt that), follow a different notational convention, or Notion is handling things wrong.
I'd really appreciate any help I can get figuring this out. I know I've worked with Horns before in Notion and not had this problem. That's what makes me wonder if Rachmaninoff is using a notation convention different from what is commonly known now.
Here's a link to the score in PDF format: http://imslp.org/wiki/Piano_Concerto_No.2,_Op.18_(Rachmaninoff,_Sergei)
Ugh! The pictures below don't show the entire image horizontally, but I think there's enough there to illustrate the facts as I see them.
Here's a picture of the PDF score section that's raising the issue, the first use of Horns in the score:

Here's a picture of the Horn (and surrounding) staffs in my Notion score of the same section:

Here's a picture of the Staff Settings for my Horns:
