Based on Hell's Kitchen, they focus on those that are leaving soon. David has gotten a lot of air time so he will be gone next episode. Christine and Felix are definitely top 5. They only have time to focus on the bottom and the top dish for each episode.
I don't know if thats really the case...
Earlier in the season they focused a lot of Christine, even teasing the idea that her meal was so bad that she was brought to tears, or constantly focusing on her cutting her self, or piercing her self with seafood. It always ends up being a sensational dish, and the tears are tears of joy from the hosts telling her to quit doubting her self. The reason we don't see a focus on christine anymore is because she just doesn't make mistakes... I mean, when your biggest blunder is a delicious tasting Strawberry shortcake that wasn't made with strawberries... you are doing something right.
I do however think the next time they focus on christine (which might be next week based on the preview i think), it may actually be something negative because at this point, no one believes she makes anything bad.
IF they followed your theory, Monti would have been gone 3 or 4 episodes ago. THey have focused on her ever since Tali's buttbuddy left. Even before hand, she was a big focus. Becky, Tali and David should be gone by now as well.. (im sure one of them will probably be leaving next week though)