I'm not sure I understand your request correctly, anyways..
Because the status is changed with old and new, you can not use "Status" for both old/new.
I mean old data has old status and new data has new status and these need to be counted with their own status.
To achieve this, at first you should re-structure your data with data-pivot as below.
Delta is calculated as following.
zn(countd(if [Pivot field names]="PR/ER Status" then [Pr/Er Id] end))
zn(countd(if [Pivot field names]="History.Old State" then [Pr/Er Id] end))
You can put sum(Number of record) as primary Axis with Color of new/old.
And Running_sum of [delta] to secondary axis.
status _ Delta 9.3.twbx 28.4 KB
Still not sure which is the VIZ to show what you want to show.
One idea have is like below.
Old status as fatter/lighter color line and New status as thinner/darker color line.
And add two bar charts to show what is changed.
Talking about flat line chart, you can not accomplish that with " Continious " line.
It's only available with " Discrete " date axis and below formula.
running_sum(zn(sum([Number of Records])))
Then created dual axis chart to show the difference overall count.
And to how individual status change, created bar graph.
I added "Negative" to how "Old status" which reduced number of item from respective status, and add positive with New Status which increased number of item to status.
-sum([Number of Records])
StatusChanges_9.3.twbx 56.2 KB