Lillebakken (2)

Please help me understand!!! I have got a copy of "Alien Registration and declaration of Holdings" from Minnesota for Nils Olson Lillebakken. In this he states that his wife is dead but in his WW1 registration Card, which he filled in 6 months later, he lists his wife as Marit Lillebakken (which is correct). He also claims to have 3 children in Norway but only one is known to me and the family. So I wonder, could he in any way benefit from giving incorrect informations on this form? Stefan