In this paper, we show that if R is a commutative ring with identity and (S, ${leq}$) is a strictly totally ordered monoid, then the ring [[$R^{S,{leq}}$]] of generalized power series is a PF-ring if and only if for any two S-indexed subsets A and B of R such that $B{subseteq}ann_R(|A)$, there exists $c{in}ann_R(A)$ such that $bc=b$ for all $b{in}B$, and that for a Noetherian ring R, $[[R^{S,{leq}}$]] is a PP ring if and only if R is a PP ring.