I need some advice with Jumpies

I am after some advice with the 3 ball patterns. Specifically Jumpies. So I can just about manage Nifty, although it's not clean, rhythmic or in time for that matter, but I can feel it getting tighter every time I try it. Jumpies however, they are eluding me. So, I can get the home base ball into my other hand, providing I roll the Bob into home base. Yet every time I try to do the little jump with Bob, I throw everything everywhere. I am a competent juggler, so I don't believe it's a hand eye issue. I think I am getting the "roll" of the throw wrong, but I have no idea how to correct it.

I have added a video in the hope it will explain a little bit of what I mean. (please excuse lock-down locks and tired demeanour)