[Nevadaref]

Rut,
I must politely disagree. Rule 9-11 Penalty part 2 on page 56 clearly states, "If the violation is at a team's own basket, no points can be scored, ..."
Now rule 9-1 Penalty 4 states, "If there is a violation first by the free-thrower's opponent followed by the free thrower or a teammate:
1. If both offenders are in a marked lane-space, the second violation is ignored, ..."
However, this only pertains to violating the provisions in effect until the free throw hits the backboard or the rim. I don't believe this statement was meant to allow the offensive team to commit basket interference on a free throw without penalty. My proof lies in the Comments on the 2002-03 Rules Revisions starting on page 70:
"Double free-throw violations changed (9-1 pen):
This change establishes a new penalty for free throw LANE-LINE violations when a player (in a marked lane-space) violates followed by a second LANE-LINE violation by the opposite team by only penalizing the first infraction. ..."

Now we go look at rule 4-45 Violation. We find that BI by a teammate during a free throw is a type 1 violation, while lane-line violations are type 3. The new exception allows the shooting team to commit a type 3 violation during a free throw after the opposing team commits a type 3 violation. That is specified by the words "lane-line" in the comments.

So in your senario, Julie, A3 may enter the lane or leave a marked lane space after B3 violates without penalty. But may not commit basket interference or goaltending as those are type 1 violations. However, A3 did just that. So the correct call is to NOT count the basket and award a replacement free throw for the lane-line violation by team B.
In short, your interpreter goofed! You are right.
Always think for yourself.