Why are you doing it that way?
If you need a PDF, the just use the export feature in InDesign. Distilling postscript is an archaic workflow and is most definintely not recommended.
One of my client requested to do PDF to be distilled using their supplied joboptions. Thats what we are doing PS to PDF.
Is there any difference b/w export PDF and PS to PDF?
There are major differences between PDF created by distillation of PostScript and exported PDF.
PDF created by distillation of PostScript loses color management and live transparency. The PostScript output by InDesign (and for that matter Illustrator and Photoshop) is optimized for direct printing, not for creation of PDF. The resultant PDF file is not particularly device independent, may exhibit transparency flattening artifacts depending upon what further processing is done with the PDF file, loses significant searchability. “Text Touch-Up” of such PDF is also hindered in many cases and impossible in others.
Creating PDF by distillation of PostScript is usually the result of bad habits of a dozen years ago continuing to be perpetuated into the present. Any reputable print service provider or publication should be able to print (or place) a PDF file exported from InDesign.