The amount attornies can charge up to (IMHO) up tp $6,000. It's a recent change. It's set by federal law that it can only come from back pay. Your contract with B & B should clearly state that. So if you are not getting back pay then B & B doesn't get paid.
It is very possible that you won your benefits in three months but there is a waiting period of 6 months.
From the SSA Planner:
"If your application is approved, your first Social Security benefit will be paid for the sixth full month after the date we find that your disability began.

For example, if your disability began on June 15, 2008, your first benefit would be paid for the month of December 2008, the sixth full month of disability.

Social Security benefits are paid in the month following the month for which they're due. This means that the benefit due for December would be paid to you in January 2009, and so on. "
Maybe that will help explain the date discrepancy.
Trudi