Balk Call

[tankmjg24]

So here is the situation. OBR Rules but I do not think it matters. Two man crew and I am the field umpire in C position with R2 and R3. RHP has a high leg kick and he picks off R3. From my angle he clearly crossed the plane of the rubber. I could see his foot go back and where it landed was well behind the extended line of the rubber.

Coach comes out to question balk. I explain that he crossed the plane of the rubber which commits him to pitch. His first argument is that this is not a balk and a legal move. I explain nicely to check his rules as it is illegal and reference the rule below.

Rule 8.05(a) Comment: If a lefthanded or righthanded pitcher swings his free foot past the back edge of the pitcher’s rubber, he is required to pitch to the batter except to throw to second base on a
pick-off play.

He then complains that there is no way I can see this from my angle.
I saw the conversation going nowhere so I replied that the call was a balk and not going to change and the conversation was over and the coach returned to the dugout.

Now here is where my true question comes into play. The coach complained to the head umpire of the association over the call. I have no clue how the conversation went. My boss in talking with me said that he was not going to get into discussing my judgement and that I was correct in the rule however he would have to agree with the coach in that this cannot be seen in a two man crew. According to him the only way you can see this is if you have a three man crew and U3 is in D position.

So what are everyone's opinions on this? To me this was an easy call due to the fact that I could see his foot go beyond his hip and then where it landed. Thoughts?