Sorry you didn't get it, it was 20 bucks for Xpresspost to P.O Box and 43 for Priority to Non-P.O Box, BOTH 3 business days. The only difference is Priority gets you signature while Xpresspost doesn't ( this is word to word from Canada post ) - yet it was signed ( probably re-routed ). Sent so much stuff in the past to Immigration, your app reaches the correct place regardless and 1-2 day doesn't really matter as they reach officers desk in a bundle.
Else, I am so particular about these things that I spent $1800 X 2 ( Travelling myself twice ) when I had to deliver/pickup passport to Canadian Embassy in India, instead of risking mail as its illegal - for my parents sponsor app while they were here in Canada