Honestly I doubt that it is a turn that is advancing it four. From what I have seen in many different areas (marts, routes, caves etc.) is that a single turn is always a 1 frame advance. However, an NPC can also advance frames without actually moving :/ I'm going to guess that's what's happening here. That's why I do it the way I posted above, as it keeps those weird frame advances to a minimum. And yeah, NPC movements vary with every delay/seed (they might even be completely random I'm not totally sure), so they're pretty annoying to try to keep track of.
Well it's not like I'm just guessing the number of 4, and I couldn't do it your way because It was an odd frame and it required a turn since he kept advancing it evenly. The way my seed worked was as soon as I entered the game, he turned before I could even blink. So, in order to find out how much frame advancement was being done after his turn, all I did was reset, enter the game and let him turn, then sweet scent without any journal flips. With the pokemon I caught, I was able to tell what frame I landed on and with a frame of 17, all I had to do is turn as soon as he turned, and there you go.
Now what I still want to know is without turning pages, would I still land on the same frame with another seed in that route?