[Andy]

I will comment based on NFHS rules, which is the only ruleset that I am familiar with.

Your reading of the rule is correct. In order for a back row attack to be called, the ball must be entirely above the height of the net when the back row player contacts it and completes the attack. Whether or not the back row player jumps has no bearing on the rule.

That being said, it is entirely a judgement call on the part of the official and it can be difficult to judge exactly where the ball is in relation to the net from the officials stand looking down. Speaking only for myself, I tend to give the benefit of the doubt to the defensive team and make the call. The reason that a back row setter is used is to have three legal hitters in the front row. If the violation is not called, it creates the advantage of having a fourth hitter for the offensive team.

I will also say, that since you are coaching JH, you may see a lot of new and/or inexperienced officials. One of the things that newer officials tend to struggle with is keeping track of which players are front row and which are back row. That could be a reason why you did not see your taller setters called for the violation in the past.