the Dow Quotes offered by the SB site tend to follow the futures price +/- a fair value, based upon time to expiry, Alan's Greenspan's Body Mass Index, and the number of candles in China.
seriously though, not just outside the NYSE opening hours, but also during them, the SB price of the cash index follows the futures +/- this adjustment, which is why the SB price doesnt always tally with the cash price which your charting system may be telling you.
even before the futures market opens, then the SB companies also manipulate the dow price to tally with the Asian/European markets, and to some extent the FX market.
hope this helps,
im going back to my sandwiches now. 🙂
FC