I hope I am terribly wrong, and so is the immigration consultant who told me that, but she said that they won't open your file until it's dude date,especially if they requested additional documents.
I have seen a trend though, that there's a bunch of March applicants who got DM and yet no PPR, and late April applicants also havent gotten PPR. Who knows what they're really doing. It all depends on your visa office, the officer checking your file, and complications in each person's case. No point in worrying. At this time all we can do is wait.