Forward and Future T Bonds

With these and other items that throw off cash flow during the life of the contract I have seen two approaches. One where you subtract the PV of the cash flows from the spot and the other where they have to subtract the FV of the cash flows from the forward. They are mathematically the same so can anyone think of a reason to keep track of both concepts of just pick one and go with it.

Mine is FV…it’s consistent with how you do spot.

Same here … but dont forget the discount factor for bonds.