OptimizeResources has no effect

I am using Aspose.PDF version 10.1 and I am attempting to create PDF files from an XSL-FO document, and it works, except that the resulting PDF is consideraly larger than it should be.

I attempted to use the "OptimizeResources" but the optimized PDF file ended up being slightly larger then the non-optimized PDF file.  I'm using the following code snipet:

  // set the name of xsl-fo file
  string inFile = @"C:\Temp\Input.fo";
                       
  // convert the XSL-FO file to PDF using Aspose load options
  Aspose.Pdf.XslFoLoadOptions options = new Aspose.Pdf.XslFoLoadOptions();
  options.UseOldXslFoEngine = false;            
  Aspose.Pdf.Document newDoc = new Aspose.Pdf.Document(inFile, options);

  // Optimize the file size by removing unused objects 
  newDoc.OptimizeResources(new Aspose.Pdf.Document.OptimizationOptions()
   {
            LinkDuplcateStreams = true,
            RemoveUnusedObjects = true,
            RemoveUnusedStreams = true,
            CompressImages = true,
            ImageQuality = 10
   });
            
   // set the PDF filename
   string outputFilename = @"C:\Temp\Output_optimized.pdf";            
            
   // save the PDF file
   newDoc.Save(outputFilename);

Am I doing something wrong?