Partner's Basis Period and Accounting Period on tax return.

Hi- I am having senior and blonde moment at the same time.
Filing a return for a client who joined a partnership on 01/01/10. Accounts for the partnership made up to 05/04/10. Have calculated share of loss ok, am confused about this "If your basis period is not the same as the partnership's accounting period, enter the adjustment needed to arrive at the profit or loss for your period"
Huh? Do I need to subract my client's loss from overall lost and put remaining amount in this box?
thanks