That massive spike to 6 million BTS (that i had to chop the top off) was the USD worker proposal that was previously funding Xerocs work (for Uptick and the the PyBitshares Library). The worker completed and as such the surplus funds were returned to the reserve pool.
This is a new type of worker that actually pays the contractor in BitUSD or smartcoin to allow a constant income despite currency fluctuations. This also has the bonus locking up BTS and increasing the supply of smartcoins
Ok, so the huge up spike was because Xerox's work was completed. Thanks for clarifying.