Check your code then, I've monitored my earnings for a whole hour at a point where I had 0.18BTC/day in bids and I was getting 0.0003125 BTC every 5 minutes. Do the math and that amounts to 0.9 BTC per day. It's been like that for quite a while and I'm always earning 50% of the per day bids.

It seems to be fine now, it wasn't before though.