If you want to add more journals, but not enough that will take you to the next reward level, here's how to do it!
Let's say you want to order 12 journals. Pledge at the 10 copies reward level, but then add on the unit price for each additional journal. So the unit price in the 10 copies tier is $15 CAD ($11.32 USD). So a base price of $150 CAD plus another $30 CAD for 2 more copies equals $180.
OK but will this impact my shipping costs? Maybe.
For North America, the cost doesn't go up that much so I will not increase the shipping rate.
For the rest of the world, the costs go up with weight, so expect to pay a little bit more per journal in shipping. You can see the rate for shipping for the next higher tier, so it would be somewhere between the two tiers. Hard to be specific because there are a bunch of variables. Hope this helps!