I imagine, that those numbers:
Verge (lyra2v2)   1560.410948 XVG   7.368 k   1 577 830 (2%)   41 mins   -   0.00318
Unitus (lyra2v2)   31.80890638 UIS   7.496 k   1 157 806 (0%)   42 mins   12.6 GH/s   0.00020
MobileCash (lyra2v2)   20.2 MBL   930.327   1 042 248 (46%)   5 mins   12.6 GH/s   0.00005
telling what profitable specific coin is. And for single algorithm higher number means higher profitability (linear). And following this, when 'stratum' picks less profitable coin, pool earns less. For me it looks like pool picks coins randomly - most profitable and less profitable too. Someone asked about that before in this topic.
Maybe I dont understand it well