Substitution procedure

[Tony.oe4]

NFHS ruling.

Situation: Two players are in the substitution zone (8 coming in and 2 going out). R2 recognizes the substitutes and wave them to exchange. Player 8 going in does not step into the court in the substitution zone but steps over the attack line and enters on the libero exchange zone side of the attack line. R1 blows his whistle and assesses unnecessary delay. This happened again later in the set and the R1 assessed and unnecessary delay red card.

My question is where in the rule book or case book does it say that when making the substitution exchange, it says the player coming in can only enter between the attack line and center line? I have looked over both books thoroughly and cannot find anything. The only thing I could find is rule 10.2.7.2 which states "enter the court when indicated by the second referee." There is no other reference that I can find about "where" a substitute must enter the court.

Was this R1 just being overly officious?