So what happens when a shift does not find a block? Is all that work not paid as there is nothing to pay it with? See the personalized stats example below.
Recent Shifts
ID Ended Shares (yours / total) Blocks Found
9538 OPEN 6656 / 61465088 0
9537 2014-03-05 00:45:01 13824 / 151146495 1
9536 2014-03-05 00:38:38 13824 / 150294528 0
9535 2014-03-05 00:32:13 11776 / 151369727 1
9534 2014-03-05 00:25:47 6656 / 151110656 0
9533 2014-03-05 00:19:17 10240 / 150097920 0
9532 2014-03-05 00:12:47 12288 / 151072256 0
9531 2014-03-05 00:06:22 10240 / 152461821 2
9530 2014-03-04 23:59:52 7680 / 150917119 1
9529 2014-03-04 23:53:22 11776 / 152552446 2
Also I don't think the personalized stats recent shifts blocks found correlate with the personalized stats earnings log or the main stats recently found blocks.