Question about applying for Taiwan ID for first time

I was born in the US and had always had a US passport. I am planning to apply for a Taiwanese passport with 僑居stamp. If i enter Taiwan with this new passport and want to apply for a Taiwan ID I have to stay in Taiwan for a year. But according to ROC law, if I stay over 4 months in Taiwan I will get drafted into the army. My question is whether if the army people start counting 4 months when I enter Taiwan with the ROC passport or do they start counting when I apply for my Taiwan ID and 入籍 ?

Both of my parents hold Taiwanese passports and Taiwan ID.

http://www.oriented.org/legal/ID-4.shtml