Bad mining pool results

[chromosoma]

Guys, I am running 4x Antminers U1 with cgminer on default speed from PC  Ports. (Diff 8, HW 3%)
My pool (50btc) see  my Hashrate, but somehow i only get 1/10 of estimated earning.

here is example:
I have 6.4 GH/S, the pool website says i will get  about 0.0117 BTC  in 24H at this hashrate.
But somehow i only  earn 0.000075 BTC / HOUR (or 542 Shares/hour), that will  make only 1/10 of what server is promising.

What am i doing wrong?