There are two tables, one shows the live bitcoin price in various currencies. For example:
Dollars US$601.01
Euros E 541.06
...
The second table, is 'My Balance'. For example:
Bitcoin 0.5
Dollars 300.50
And since the start of the thread, the quantity of bitcoins has gone up by 0.00000224.
It seems to me like the balance on that exchange is kept in USD, and not in Bitcoin. Therefore, your balance tends to increase or decrease based on the price in USD. I can't be completely sure though. Something isn't right with that exchange.