So I am having an issue with having multiple shipping promotions. I am selling $1 comic books for charity and I have set up multiple shipping promotions to help people out. 1 book is $5 shipping, 2-5 $9, 6-50 $16, and 50+ books $36. How I thought it worked was since you have to set a minimum order amount for each promotion, that whenever the buyer would meet the minimum order amount that it would automatically switch to the next promotion. So far that is not the case and the buyers are taking full advantage of it. I have had to pay out of pocket for shipping a few times when I'm not really doing this for the money but for charity (I am literally making a few cents per item sold.)
Most recently a buyer bought 14 books which should've changed the shipping to a flat-rate $16 but the shipping promotion he received was for the 2-5 books amount of $9. I don't understand the combined shipping rules because adding a fixed price amount per item will work up to a certain point. For instance, if i added a rule that would add $1 per additional book they bought; after they buy 10 books, they are overpaying for shipping. I know how many books I can fit into each flat-rate shipping box/envelope (up to 5 books in a flat-rate 12in x 9in envelope, up to 50books in a medium flat-rate side load box, and anything more than that requires at least 2 medium flat-rate boxes). I am really just trying to give a good price for a good product at fair shipping for charity and it feels like that buyers are looking for any loop holes to get the best deal and I know that it probably because of my inexperience when it comes to setting up a eBay store. Any help would be greatly appreciated!!