Many would have struggled to understand Garret's point, but Khan's broader perspective allowed him to realize what most scientists could miss.
The attunement level didn't differentiate between humans and aliens. It simply represented how much flesh the mana had enhanced. Khan had found the scanners reliable even after the transformation, but the training session inside the pool had probably brought a more revolutionary change.
Transforming Khan was the whole point of the new training method. The pool had to attempt to evolve him before reaching full attunement. That meant developing higher-level tissues, which required and could accommodate more mana.
In short, Khan's flesh now needed more energy to get an additional point on the attunement scale, and that had a retroactive effect. The amount of mana inside his body didn't change. He didn't even lose his progress. The pool had increased his requirements, which the scanners reflected in that regression.
