Is the new infinity edge really a better scaling item? (Repost due to important error)

Edit: I made an important mistake in my original calculations, so I'm reposting

Tl;Dr: It's worse until 56% damage reduction, and it is likewise significantly worse in the early and mid game, but somewhat better in the late game Assumption: league calculates true damage conversion based upon the equation of ((true damage conversion) + (total damage - true damage))

Hypothesis: Given the new changes, at what damage reduction is the new infinity edge give more value, given variables such as armor pen. are constants (zero).

Introduction: I am an ADC main. After the new changes, I noticed a considerable difference in the power level of full crit builds, particularly in the early and mid games. However, riot did advertise the new changes to make the infinity edge a "scaling item", which I interpret as meaning it is much better in the late game. I wanted to figure out if this is actually true by coming up with an equation, read basically as: "+50% infinity edge damage - 20% true damage conversion". I had to make some assumptions, but I'm not sure what the effects of the assumptions are.

Final equation: y = ((x2.5)-(xa2.5))-((2x*.2)+((.8x2)-(.8xa2) , {x>0} Definitions; y: total difference between +50% damage and 20% true damage conversion x: base damage before crit Left side: the +50% damage equation Right side: the 20% true damage conversion equation x>0: x (base damage) cannot be less than 0 a: % damage reduction

Broad interpretation: base damage 250% - total damage reduction - aggregate converted damage + 80% base damage 200% - total damage reduction, base damage cannot be less than zero

Findings: at about a = 56%, y = 0. The the graph always having a negative slope this means that the new true damage only scales better at 56% damage reduction. This occurs at about 120 armor (found via practice mode).

Conclusion: When only those two variables are compared, at less than 130 armor old infinity edge did more damage. Likewise, I conclude that ADC's actually scale somewhat than before when building critical damage (note without taking into account other item changes or efficiency, just the changes to that one item). I believe this statement is legitimate because ie was and still is a key item for crit builds. Moreover, crit builds are remarkably worse in the early and mid games.

Example for final claim: at 500 base damage and 40% damage reduction (66 armor), the ie build would deal about 70 damage more per crit auto than the current infinity edge, at 30% (~40 armor), 115 per crit.