I think [speculation?] it is because they are having problems with their first batch which keeps increasing the delays and drawing the process out. Their window of opportunity keeps shrinking as BFL_Josh stated the issues keep eating through the padding of time they originally estimated their first deliveries.

Actually, they have pretty much said so in context of sourcing parts for their first batch. A competitor forced them to upgrade the hardware and everything that goes along with that. (Power/Heat issues apparently cropping up as well as parts sourcing issues)

They also briefly mentioned paying for expedited fabrication/shipping of the chips. (If I recall correctly)

There is a story that remains half-told as to why they would have to shell out the extra cash for that. I am not out to seed doubt, it just means like any other company they have issues that should be resolved with any new creation. It is expected.