Is it better to sell packages of things rather than individually for size tier charge?

I am going to be selling items with my own art on them (imagine refrigerator magnets of cartoon animals). My original plan was to sell them individually, with discounts as people buy in bulk. There are a lot of different “animals” so the assumption is that they would buy 10 or so at a time for variety, and discount.

I got a few of the individual items added on Amazon Seller, each with their own GTIN, and was about to place the order on Alibaba.

That’s when I noticed the FBA fulfillment fee. Now I have a few questions-

First of all, does this include the .99/sale / $40/mo that I agreed to when I started this, or is it on top of that?

My main question has to do with the size tier. This looks like I will be charged around $3 per unit, up to 16 oz. Am I reading this right? Keep in mind, I was planning on selling refrigerator magnets individually. On top of Alibaba production/shipping costs, I would have to sell each magnet at >$4 to break even.

I know this is a basic concept, but bear with me.

According to my Alibaba supplier, each magnet weighs 10 grams (0.3 oz). It would take 45 invidual magnets to weigh a pound (16 oz), and if I understand the size tier chart correctly, this would still only cost me 3 or 4 bucks.

Based on all this, does it make more sense to just sell a package of 40 “animal magnets” rather than individually? (of course it does, but am I understanding how this works correctly??)