why do we have negative unexchanged balances? 


May 26, 2014   19   12,107.5 MH/s   0.13545060 BTC   -0.04448157 BTC   5.45451985 BTC   5.54548888 BTC
May 26, 2014   18   12,348.7 MH/s   0.00989370 BTC   -0.12084085 BTC   2.93793335 BTC   2.82698620 BTC
May 26, 2014   17   12,482.8 MH/s   0.00275080 BTC   -0.07241191 BTC   1.10503311 BTC   1.03537200 BTC
May 26, 2014   16   12,523.5 MH/s   0.00362010 BTC    0.00158857 BTC   0.81978769 BTC   0.82499636 BTC
May 26, 2014   13   13,151.6 MH/s   0.00489702 BTC   -0.04594048 BTC   1.95759117 BTC   1.91654771 BTC