Applying Average Line in Chart

Hi,

I am needing to average an "average" line on my chart but when I apply it using the breaks, it turns out to show an average of the sum of all averages for each break.

Can anyone please advise on how to show the correct value on the chart so it shows as a horizontal line?

I am looking to get the value of 98 instead by using the formula =Average ([Turnaround Time (Minutes)])  In Break

Thank you for your help,

Jaspal