Hi basically if your case is a simple one and the OR has looked at and dealt with everything he can within the first 3 - 6 months or so he may decide to allow early discharge so that your file is not hanging around longer than is necessary. No assets, nothing improper, no disposable income. This is a typical scenario for early discharge.
From my experience it is just better to think that you will have to wait the whole 12 months.
I went bankrupt in Nov 07, and then was told that I would be up for early discharge on the 23rd June, only to then be told at the beginning of june that they had changed their minds and that it would be Nov 08. They didnt give any reasons for either decision!
It does actually go quite quickly - i only have 3 months left now.