To define a custom distribution, your macro code must first set the cell selection to point to both the assumption cell and a table containing the custom data points. You can do this using the Union object with the Range object to append the table's cell range to the assumption's cell location.
Even if set, LowCutOff and HighCutOff are ignored for custom distributions.
Parm1 can only be set to cumulative (True) if the table of data points has two, three, or four columns.
Call CB.MacroResult afterwards to determine whether the command was successful.
For more information about defining custom distributions using a data range, see the Oracle Crystal Ball User's Guide.