Calculating gear ratio progressions isn’t all that big of a deal; and what you’ve found is pretty standard stuff for most bikes’ drivetrains as delivered.
Essentially, that there’s a lot of overlap in the middle, vintage half-step setups notwithstanding.

Using the gear-inch calculator also accounts for wheel and tire sizes, which is useful when comparing different bikes in your stable.

I think what’s confusing people is that you’re looking really hard at the ‘lateral measurement’ between the cogs as some sort of indicator. I mean, the cogs are always going to be evenly spaced, and the point on the cassette where the ratios overlap has only to do with the number of teeth on the cogs, not where they are in the order.