Re: ANN: BITMAIN has Tested Its 28nm Bitcoin Mining Chip BM1382
Release B4 
they are likely using the last few days to ensure happy B1-B3 customers. By the end of the week almost every order should be shipped and they can offer 48-hr shipping on B4 onwards.
also, they probably need a few days to redesign the miner to achieve 500GH if its possible.
500GH Would be devine. Hopefully BITMAIN can do it.
They told me they won't redesign it (I asked more info the DC/DC component).
I got one unit that run at 250 mhz at ~503 GH/s (0.001% error rate)
The other one, running at stock at ~434 gh/s (Any OC kill the performance)