Bundy,
It is entirely possible that you are correct. I have the ability to add too much rigor to many things in my life. Wife reminds me of this constantly.
But let me ask you these hypothetical questions Bundy.
What if you were asked to take your jack recipe to make a substantial wheel of cheese. Lets say a bigger 8-10kg wheel that is 14-18 inches in diameter.
or
What if you were asked to take your jack recipe to make a bunch of small tiny wheels (as presents or stocking stuffers!), that were only 2-3 inches in diameter.
Would you still use the same weight for each recipe variation?
I would imagine, (and i am no expert), that a consistent PSI would be the only way to make the adjustments to the different sized wheels.
Your recipe indeed calls for psi settings of: .3537psi for 15min, .5306psi for 30min, and finally 1.415psi for 12 hours. If you wanted to scale up, or scale down your wheel size, then using your recipe psi figures, it is easy to figure out how much weight to add to your big wheel, or how much weight to take off for your tiny wheels.
And some recipes do in-fact call for PSI.
Peter Dixon is an example.
Yes, perhaps i overthink it.
But for me, the constant tinkering, the constant processes improvement, is at least half the allure of cheesemaking.