People seem to switch around quite a bit to try to avoid it, and there's no real consensus on what foods are best.
I honestly don't understand why you feel like there needs to be one specific feed that works for every single chinchilla. All chins are different, and all people want different things from feeds. Over, and over people have listed what feeds are safe for chinchillas, and doesn't cause death. Try one and if it works for you, stick with it. If it doesn't try another.
I'll start here and tell you what I specifically see wrong with the feeds listed on the Purina Lab diets website.
Autoclavable Rabbit Diet- Protein too high
Rabbit Diet- Corn as second ingredient
Certified Rabbit Diet- Corn as second ingredient
Certified Hi-Fiber Rabbit Diet- Protein too low
Rabbit Diet H- Protein too low
Advanced Protocol PicoLab Natural Sunflower- not a feed, just sunflower seeds.
Prolab Hi-Fiber Rabbit- While corn isn't the second ingredient, it's too high on the list for my liking.
Prolab Rabbit Diet Hong Kong Diets- 4 ton minimum, corn too high up on the list anyway
PicoLab Rabbit Diet HF- This is the first one I have found on there that could work, but I would like someone more in tune with what chins needs for vitamins/minerals to take a look at it.
PicoLab Laboratory Rabbit Diet- Fiber too low.
Once again though, I honestly don't even see the need for someone to try any of these, or any other lab diets, on their chins as what they are using is apparently working for them. Like Tiffany said, these are also very expensive considering how many chins some of these people have. It might work for someone who owns pets (well a whole bunch of them as I highly doubt these come in anything less than a 50 lb bag).
While I do definitely appreciate the consistency of the feed I'll stick with my corn free diet so that I know my chins aren't being filled up with fillers instead of what they actually need. Just my personal opinion.