Warm-ups to jerseys at bench

[just another ref]

All twelve members of team out come out wearing their warmup tops instead of their jerseys. Before the start of the game they all change into their jerseys at the bench. Ruling: Officials assess one technical foul against Team A and an indirect against the head coach.

I have seen this before somewhere. Was this a case play or interp, or has it just been on the study guide before?

I say it is true based on 10.4.4B which states that similar multiple infractions at the same time are charged with a single team technical rather than individually and, as is this case since bench personnel are involved it is also and indirect on the HC.

But the answer key says false.