When adding a new Sales Forecast to the list it gives you the option to enter the forecast for an entire 12 months.

Sometimes a forecast is created with only 3 months left of the financial/Calendar year.  In order to enter the information you need to scroll all the way to the last couple of weeks in the list in which to enter the data.

Customers would like to have the option to show the weeks that require updating in order to make data entry easier and quicker to complete.