Owner Occupy Address for Tax purposes

[Melody Gerig]

I just recently bought a duplex and I am going to be living in the upper unit as an owner occupy. The problem I am running into is that the Upper and the Lower units have two very separate addresses, separate street names even. The lower unit's address is the one that was used for the sale and is attached to the mortgage and is used for tax purposes. So my question is, do I use the address that I am actually living at or should I use the one that is attached to my mortgage when I notify my state of my change of address? 

Thanks!