I see both sides here. As you point out, the rules and the FAQ make it pretty clear what the answer is to his question/proposal. On the other hand it can be frustrating not to get a direct answer to a written inquiry. But back on the first hand how important is it to answer something you already answered in the FAQ? Then again, it's not very educational to ignore someone, so surely someone could have found 10 minutes to address the question in writing. But who knows how busy they are or if something just slipped through the cracks?
Maybe the question is really a "why" question as in why won't the JREF put acceptable odds in the MDC? I'll take a crack at answering that, but my answer would be why *I* would not do it.
In every negotiation, and the MDC process is a negotiation starting with the offer by the JREF, you don't pin yourself down to anything you don't have to. There is no advantage to the JREF defining an accuracy level without also defining everything else around it. Doing so could easily put them in a corner and force them into an unfair protocol.
If the JREF were to take the extraordinary step of defining accuracy along with a protocol to ensure they are not being taken advantage of, it ceases to be an open challenge and becomes at least in part a specific challenge. That's really not the goal.
It would also force a take it or leave it approach. That is the antithesis of the rest of the rules, which demand an open and fair negotiation of both the protocol and the accuracy level. If the JREF were to then allow negotiation of their prescribed protocol, then negotiation about the accuracy must follow in kind.
And that, of course, would bring us right back to where we are now, so why waste the effort?