I can't speak for the Oxypowder folks either, but I will say that I have always had good experiences with them in the past. And they recently won the 2007 Better Business Bureau's Award of Excellance. So, they can't be that bad of a company.
I would suggest that you call them up and ask the question directly. Because one of two things would happen. You would get your answer, which is what you want. OR you will alert them to a problem on their website, which is something I'm sure they would be grateful for.