Lower Amazon fees for more expensive product

I have 2 products. Product 1 contains Item A. Product 2 contains Item A plus Item B. (A bundle of 2 products)

Product 2 is $9 more expensive, yet the service fees are almost $3 less than Product 1.

Anyone know why that could be? I thought sales price was part of the equation for the fees. The package size between Product 1 and 2 is identical, and product 2 weighs slightly more but roughly the same weigh.

I’m wondering if the cheaper fees for Product 2 is correct and I’m being over charged for Product 1, or if the fees for Product 1 are correct and I’m getting undercharged for Product 2.

What am I missing?