2003 amos away (Eruvin 35a)

The gemara says that if the eruv rolled three amos after you had placed it 2000 amos away it's valid. What happens if l'chatchila you put it 2003 amos away? I wanted to do some research on that because I could hear both sides but I haven't had time. If I have time later I'll look around. In the meantime I wanted to know if anyone had heard anything.