When you print to file using multiple tiled pages, Illustrator creates only one PostScript file that contains only a single tile or page. Usually, Illustrator includes the last tile or page in the Illustrator document in the PostScript file. For example, if you print a six-page tiled Illustrator document to file, Illustrator includes only the sixth and last tile in the PostScript file.
When you print to file using separations, Illustrator creates one PostScript file. When you distill this file, Acrobat Distiller creates a multiple-page PDF file. The number of pages depends on how many plates you printed.