I use Inventor 10 at college and i dont have 2 UCS arrows,just 1.
Can i quess what u mean is EACH MODEL has a different UCS, i.e you have problem like when u want to view the top it goes to the bottom when u want to view the left it goes to the right, or when u insert or open a new model the UCS is different every time? if this is the case then i can help as its a simple matter of making sure your in the right view before you begin to sketch and save.
not sure if i have helped???