The way modification acts are voted and then enter into force is quite complex and cumbersome. It is very common for a modification act to do things like removing a sentence from another act, a sentence that, in the meantime, has been changed by an urgent decree or another modification act. What is the final text of the modified act? How do you solve this? Or can you solve this? Or, which authority have you got to solve this?
This kind of "merge conflicts" require attention by a competent authority, either a court or a legislative body. Generally speaking, a resolution a merge conflict is an _authentic interpretation_ (http://en.wikipedia.org/wiki/Authentic_interpretation).
There are publishing houses that, for a quite big amount of money, will tell you "there is conflict here, these are the chances for interpretation A, these are the chances for interpretation B".