I think that's probably on the trade side of things. Where can you get agreement between partners to allow commodities to be exchanged at something the market feels they're able to do? So if a market can serve a 0.1% economically, that might be what's negotiated. Or they may say 0.2%, 0.5%, or even 1%. I think it comes down to what industry feels it can economically undertake transactions at, whatever that threshold is. That's where these things tend to be negotiated.
On February 26th, 2013. See this statement in context.