The mention of "the normal 2 MP for Bypassing in Open Ground" opens the question of what is normality.
The Bypassing in Open Ground is derived from the MP spent in Open Ground, which is variable.
So, is the tracked vehicle MP cost considered the norm?
Wouldn't the rule wording be better, indicating that the normal MP cost is 1?
As much as examples are the rules, isn't it strange nevertheless that an example alone contains crucial data that could - I venture even : "should" - appear in a rule paragraph?
I dare say that the rule could simply state that a Narrow Road hexside costs 1 MP, regardless of BU/CE status...
I think that I always played that Narrow Roads cost 1 MP per hexside, before I tried to answer this rules question, though.