I found some information that might help you, but also it's confusing a bit to me.
http://www.cic.gc.ca/english/information/offices/canada/mississauga.asp
RPRF payments or other correspondence:
CPC Mississauga
P.O. Box 6100, Station A
Mississauga, ON
L5A 4H4
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http://www.cic.gc.ca/english/information/offices/canada/ottawa.asp#faq
FAQ #5 sounds like original police certificates should be sent to the Ottawa office.
Send original Police Certificates to:
Case Processing Centre – Ottawa
Documents request
365 Laurier Avenue West
Ottawa, Ontario K1A 1L1
However, for the Ottawa office, it says,
"permanent resident visa applications from the United States and Canada, after they have been received and deemed complete by CPC-M or CIO-S."
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I remember reading posts from people here asking where they send Schedule A and PCC and the Mississagua one (P.O Box 6100 one) is the address they were advised.
I was hoping if someone knows which address would be the right one for people who might need to send the documents in the future(includine me. haha).