Just to get back to the topic, N1 can be and regularly is more than 100%.
100% is just a number. When you look at the op limit speeds on big fan engines, thay are all over the place. e.g.
CF6-80 B2 N1 117.5, N2 112.5
RB211-524 N1 110.1, N2 107.7, N3 99.2
Often the tacho generators used by the engine manufacturer are whats in the parts bin. After all as long as our limits are presented in a consistent fashion, it matters little what the actual number is and what it really equates to in RPM. We are operators, not designers.
There was a long thread on this subject some time back, perhaps a search would help you find more info.