Okay, I looked at the code and I think what is happening is that the first five statuses (sleep, poison, burn, paralyze, freeze) all map to the same status numbers (1-5) in both icon_statuses.png and statuses.png, but then after that is different. Status number 6 is "badly poison" in icon_statuses and "faint" in statuses, and status 7 is your custom status in icon_statuses and "pokerus" in statuses. In other words, your custom statuses are not lined up correctly, the way that the first five statuses are.
To line them up, what you should do is shift your two custom statuses inside "icon_statuses.png" down by 16 pixels (one icon height), and simply leave a blank spot between "badly poison" and your first custom status. Then, give them IDs of 8 and 9 rather than 7 and 8, that way it doesn't interfere with pokerus/faint in statuses.