Your pretty close to me and the last flat rate box I shipped to Canada took about 20 days. I sent it flat rate registered mail (for security) and it cost about $25 to ship (the thing sold for $600). From what I remember from the ordeal is the flat rate boxes from the PO didn’t have an international tracking option (if you use your own box and get priority it does have tracking) it has a customs number and doesn’t track, it only scans when it’s through customs but the PO can track it, they may not like you for making them do it but they can. I remember going in every day at lunch and asking about the package after the person that won started to send complaint emails and I would go home and send him updates.
http://ircalc.usps.com/PopUps/PMI.htm
Hu, looks like the policy has changed from when I shipped to Canada it was all flat-rate didn’t have tracking but I still don’t understand why some flat rate don’t track but all priority (with your own packaging) does.•Tracking to major destinations. Note: Tracking is not available for the Priority Mail International Flat Rate Envelopes or the Small Flat Rate Priced Boxes.
So I guess if it was any flat rate box but small you do have tracking.