Bucketing Order Hour and Attended Hour

I want to do some more bucketing, but not sure how I can make it work. 

We want to look at mobile sales for our General Admissions. All our sales are currently through TNEW. The only thing I could come up with would be to try to group things by the time between [Order Hour] and [Attended Hour].

However, when I try to bucket things (something like 

 )

it won't let me use flat Order Hour. It keeps pre-totaling things. I want to say: "Show me the count of tickets where [Attended Hour] is equal to [Order Hour]", or "Show me how many people bought tickets and then visited within an hour".

How could I make this happen?