Hi Yashar, I think I know where the issue is.
The Send Table Data is only connected to the first step of the waterfall. 
Since the waterfall output is only a number, changing the Send Table Data variable won't work.
We're working on improving this flow, but for now I propose the following solution. 
You need to create as many Send Table Data as you have providers in your waterfall 😌
I know it's a little tedious but it's the only option for now. Hope it helps.