Cumulation

Hello
I have the following problem.

I would like to display an ideal call-off history of a contract in PowerBI. This should be displayed in a line chart.

For this I have the following data:

- Start date of the contract
- End date of the contract
- Total quantity of the contract

From this I calculate the duration of the contract via DATEDIFF( Startdate,Enddate,DAY).
Then I divide the total quantity by the duration and get my ideal call-off per day.

Now I would like to represent the whole cumulated but find no correct starting point for the measure.

For better understanding I have added a sketch to show the goal.


I tried GenerateSeries fct and the DAX Pattern Cumulative Total but i only get one specific data point in my line chart and no line