You are wrong 20/20 is not perfect vision in absolute terms.
does AVERAGE Vision mean perfect vision?
I don't think so!So please read carefully!
as you probably would know 20/20 only being the average standard vision by definition.
The 20/X acuity measurement system works by comparing a person's acuity to that 20/20 standard.
A person achieving 20/15 (= 1.333...) would have a 1.33 times better acuity relative to the 20/20 standard.
but you are claiming that "comparing factor" being some mysterious "distance of perfect vision"
The math is correct !
As already mentioned at another thread by Johnlink that factor being a dimensionless number.
So in physical/math. terms you are claiming
ft/ft = m
unfortunately that's a bit odd and I doubt the scientific community would accept it as a valid math.
It raises the question where does that dimension "meter" suddenly come from (and why not ft or miles or any other unit).
For a better understanding what you are meaning let us assume a slightly hyperopic person (refractive state +0.75D) achieving 20/13 vision at the snellen chart.
So would you call that hyperope a 0.65 myope?