There is a macro you can run that will look for the amount column in the detail table and will right flush it. See   How do I get FIMS macros on my machine?  if you need help in  loading the macro onto your workstation.  

To run the macro:
  1. Merge your data as you normally would.  
  2. Go to Tools>Macro>Macros and choose the option RightFlushAmount and click run.  
  3. It will go through every statement and right flush the amount column.     Note: If using Word 2007, go to View>Macros.