Update your "TimeGroup" formula with it.
In stead of just comverting the Qlog1.Call In Time field from text to a time field it will also change it to the half hour time...for example
9:17 am will become 9:00:00 am
10:34 am becomes 10:30:00 am
10:29 am becomes 10:00:00 am
etc.
Now all your data falls into 1/2 hour fields to the second.
By doing that you can change your chart from grouping every hour to grouping for ecery second. Since this field converts to only displaying every 1/2 on the second you can get counts per 1/2 hour.
Make sense?