I noticed that most of Indians here in the forum afraid that the 28 days are not enough to issue the PCC and send it out to DIAC, i understand that its risky. However, apply for it and they will give you a paper the proofs that it is "in process" scan this paper and send it out to DIAC which will protect you if you couldn't have the PCC within the 28 days, and keep your case officer uptodate always!
Good Luck,