Balk or No Balk ?

[Forest Ump]

A little help please:

13-15 house league. Double elimination playoffs. Semi-final game. Pitchers are not the best for this team due to pitch count using up better pitchers early in the competition. I mention this to see if it makes a difference.

R3. Right handed pitcher steps on the rubber. He apparently tosses the ball from his right hand into his mitt and then takes it out. When I say toss, he kind of flips it in the air a foot or two so that it lands in his mitt. I actually did not see it as I had turned my head for a split second to check the batter as he came to the plate. The BU called a balk. I told BU between innings that I didn't think it was a balk. I didn't see the advantage the pitcher was getting. I thought it was more of a don't do that? Now I'm thinking about the three things a pitcher can do from the rubber and tossing the ball into your mitt is not one of them. I wish I had actually seen it.

What say ye.
Balk or No Balk ?