Profit and Loss Adjustments
You can make profit and loss adjustments on a quarterly basis.
To do this, go to Profit and Loss and enter an adjustment. Select the period of time the adjustment relates to, and save it.
To remove an adjustment, you must be viewing the Profit and Loss report in Quarterly view.
Do this by going to Your account > preferences > Profit and Loss dates > [set to quarterly] and save. Then go back to the Profit and Loss page, edit the adjustment and change it to zero.