Recognizing Ki Signatures

[Ryuujin]

Something has me confused. You know how the characters often can recognize each other from afar by their ki signatures? Well, there are also times when they don't recognize each other.

I can think of Piccolo fusing with Nail...not surprised the unique ki signature got altered. But what about Gohan's Chou Powerup? I don't see how the uniqueness of his signature would get altered.

Can someone clear up for me and everyone else exactly under what conditions someone's unique ki signature would get changed, and how?

[Domon]

It's fiction. There's no real reasons other than "just because" or "Toriyama decided to have this happen/not happen."

[Xyex]

I'd say it was around the Cell arc that they learned to tell the pattern of an energy and match it to a person. The only instance I can think of after this where someone wasn't recognized was Mystic Gohan, but even just looking at him you can tell he's changed. His aura's different now too (it was blue on Namek and is solid white now). IMO, any time you have a change to aura you have a changed to the pattern which means SSJ Goku's pattern would feel a little differently than SSJ3 Goku's pattern, and of course, Mystic Gohan would feel different than Normal Gohan.

[Dayspring]

Another possibility is that Rou Kaioshin taps into the user's potential and more. This is why he was sealed into the sword: even weak people with no potential could still get a significant boost. Perhaps this "added" power made Gohan's difficult to distinguish.