Exactly, because there is no way to pin 'normal' on any specific wording, both interpretations follow. This is my point.
Because I can't deductively prove my view, doesn't make your view correct by default. You need to deductively prove your view, and the best case has been provided by DarkLink, thus far.
You have to pin 'normal' somewhere for the rule to be coherent.
Deep Striking, Outflanking, and Table Edge Reserves all have their "normal" way of arriving on the board, but that doesn't make Deep Striking and Outflanking "arriving from reserve as normal."
Likewise, just because Outflanking and Deep Striking are exceptional forms of reserve (they have very specific requirements), it doesn't mean they are not "arriving from reserve as normal."
The FAQ is a sensible place to look for clarification, not because the question is about the issue at hand, but because the question provides description for rules that are.
At the moment, there is no single way to follow the Tunnel Rule.