Foul During AP Throw-In

[Sven]

Here's the situation that occurred tonight in a boys' varsity game (NFHS rules):

Less than 5 seconds left in the second quarter -- held ball called. Arrow pointing to A's basket.

During the throw-in (while ball is at A1's disposal), a foul is called on A2 prior to the bonus. B's ball at spot of foul.

Arrow is not switched. Still pointing to A's basket. Ball is put in play by B and time expires in first half.

After replaying the scenario and some discussion with the scorekeepers, the floor officials are unsure about the proper arrow direction but will look up in the rule book during half time...

They ruled that the arrow should be switched. B's ball to start the third quarter. I believe this was a mistake on the grounds that a foul by the throw-in team during the throw-in (ie. before it has ended) does not cause the throw-in team to lose the arrow.

Looking for confirmation and a rule or case book citation. If I'm wrong, I stand corrected.

Sven