To avoid SPILL error using the ArcGIS Function in the Excel table - convert the Excel table to a range, run the ArcGIS for Excel function outside the table. This can be done by placing it in the cell two columns to the right of the last table column. Using the Copy and Paste with values option remove the formula from the Excel sheet. Next, delete the column between the Excel table and the newly added columns from the function. Finally, resize the table to incorporate the newly added columns within the table area.