If you want to use Canada Post Calculated,yes.
It's a learning curve. Since you are still using the 50 Free Auction Listings, you only lose a little time, not money.
By listing in US dollars and giving USA as a destination, with a shipping fee, you will get the same exposure in the US as you do with a dotCOM listing.
BTW, if you have items that you can use a flat rate on, then you can list another 50 items FREE on dotCOM. EBay winks at this little privilege for dotCA sellers.
And, unsolicited advice, look into all Canada Post services. If your items can be packed to be 2cm thick or less, they can go Letter/Light Packet. There is no insurance or tracking/confirmation of delivery available for this service, so you could add a few pennies as a self-insurance premium for the very very occasional loss. Shipping for $7.60 instead of $16.20 will increase your sales enough to pay for itself.
EBay gives us a lot of advice that is good for eBay but not necessarily for sellers.
