deadline value from miner is converted into share value using this equation
share = 1000 / ( NetDiff * Deadline + 1 ) 0.75
where NetDiff (network difficulty) is calculated by Block0-BaseTarget / Block#N-BaseTarget
note : to prevent user spamming low share, we implement share penalty of -0.001 on each submission for miners who submit nonce that has higher deadline than their (current round) own best deadline, as spamming low share is no use since pool will always pick one best deadline for every submitted nonce per round. If you use the blage miner, make sure use sorting is true.