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If number of points on a manyfold is $q^n ( [n+1]_q )$ does it imply geometric relation to $A^n (P^n)$?

Consider an algebraic manifold whose number of points is $q^n ([n+1]_q)$. Is there a geometric relation to $A^n (P^n)$? In particular, is there an equivalence in the Grothendieck ring of varieties or could there be a birational equivalence?

If there is no such equivalence in general, might some additional reasonable requirments on a manifold will force there to be such an equivalence?


Motivation: one can see that some examples of identities on the level of $F_q$ points enumeration can be lifted to geometric relations:

Is there a lift of the q-Vandermonde identity to some geometric (motivic) identity for Grassmannians over $F_q$?

Can one divide algebraic manifolds ? Make sense: $Gr(2,n)/ Gr(2,n+m) = P^{n-1}/P^{n+m-1} P^{n-2}/P^{n+m-2}$

Alexander Chervov
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