Homemade Sausage Making

On pg. 479 of mr. Marianski's HPQMS book it shows box cured bacon with a specific method of placing the bellies. For those out there without the book, the diagram shows placing 5 bellies on top of each other. Each belly is places skin side down except the one on top. I am trying to figure out why.

My best guess woud be the flexural traits of the slab. Skin side down should be a bit stiffer. That is my guess but I don't know.