Silly me, I made a comment about a practical reality that applies to 99% of light aircraft flights and someone immediately jumps in with the 1% scenario.
Yeah, but this thread was about spreadsheets and I happened to have one taking care off adjustable seat positions
I also managed to convince a CFI once that we didn't need to have 50 liter of water in the back seat of a PA28 to stay within CG limit during a test.