Who knows?
I'm not sure where I came up with that 5x figure, because I sure can't find it now. Instead I find a lot of jibber-jabber, like:
Shell: "20% more than before"
Citgo: "The additives comply with the EPA requirements"
Mobil: "Our gas meets Top Tier standards"
Speedway: "..."
QuikTrip: "We put the same level of additives in all grades of gas"
You get the idea.
Edit: I see where I got the 5x thing now. From the "Costco gas?" thread.