I want to buy multiple Custom Counters, and I want to add different logo on each one of them. How should I do that?

Good question !

Here is what you need to do in order to add different logo on each of your Custom Counters.  

Add a first Custom Counter to your shopping cart. 

Click on sur "Add new Counters" then select another Custom Counter of your choice. 

Your cart contains now one or more Custom Counters! you can customize them immediately by clicking on "Edit Logo" and add the logo you desire on each one of them.