Since the amount I paid for IV fee is higher than $330,
-Why did you pay $70 more? It seems the fee of $400 includes the IV porcess fee of $330 and AOS fee of $70, but you paid an extra $70 for AOS (I-864) fee. But you did not pay the IV security surcharge fee of $74 yet.
and I wonder if that's the same IV fee?
or would my dad have to paid another IV fee at the time of his interview?
-Your father may need to pay the IV security surcharge fee of $74. You may send your dad the receipt of your NVC payment of $400 and $70 (scn, email and print-out) and see whether he can get the deduction of $70 for the IV security surcharge.