For a bond issued at par: over the life of the bond CFO: Understated CFF: No effect Tis is a correct statment? Please correct me if I am wrong

There would be no overstatement/understatement of either CFO or CFF. CFO would represent exactly what it is supposed to represent.

i agree with map1

I think you only get an effect if you have a discount or premium bond because you have to amortize it to its par value each period until maturity.