YES - if you are sending through Canada Post Xpresspost service, please send it to PO Box address. Make sure you include a copy of your PPR e-mail; also you can indicate PR application number on the envelope (personally i didnt do that but i read some where on this forum). It took around a week in my case to send the passports and get them stamped with PR visas - again this timeline could vary from case to case, but the whole process wouldn't take too long !!
Congrats for PPR and good luck with rest of the process.