[DJ_NV]

Ok so let's deal with this first with the play with a flag, and just for fun we'll remove the flag and see what happens with the IW.

We're going to ignore the whistle (4-2-3-Note) because there's going to be an accepted penalty. A is going to accept the DPI foul and so you will march off 15 from the PS and auto first down, so A 1/10 @ A-47. In this case the clock is going to start on the RFP (3-4-4-i, 3-4-2-c).

In this situation you're lucky because it's the same result as if there had been no IW.

Now let's look at it without the flag. And furthermore, let's examine what would happen if a) the IW was before B intercepted while the ball was still loose, and b) the IW was after B had intercepted.

In a) there is no option for either team. The ball is still loose due to its status as a legal forward pass in flight (touched, batted, muffed, it doesn't matter...it's still a legal forward pass until it's complete, incomplete or intercepted) so the down must be replayed. End of story. Clock on the RFP (4-2-3-a, 3-4-4-i, 3-4-2-c).

In b) now we have a ball in player possession so now that team has the option of replaying the down (which they're not going to do) or taking the ball at the spot that the IW was blown(which they will do). So B 1/10 @ the spot/yardline when the IW was blown. And you know the spot because you had a beanbag down at the spot when you heard the IW, right? Clock on the snap because even though there was an IW, B was awarded a new series (3-4-3-b).