Shipping multiple items not much more than shipping one? o_0

[tristen1230]

Okay so I used auto calculate for some items I was going to ship. For one it says 9 dollars and something but for 4 it only says 10. Why is it a dollar more to send 4 times the weight? This is Expedited Shipping (Canada Post Expedited Parcel) in Canada.

[dmil8030]

For items too thick to ride Lettermail, the price really jumps up with that extra millimetre.  Is this the site from which you are getting your rates?

http://www.canadapost.ca/cpotools/apps/far/personal/findARate?execution=e1s1

Are you using metric measurements and weight to determine the cost?  I know it appears to offer a choice, but you do not always get accurate results if you use the old imperial system. 

[pjcdn2005]

That's probably because expedited shipping prices are based on the volume of the package more than on the weight of the package.