manually place a data point on a line graph

[dreweezy]

I've got a line chart showing the running sum of a specific category. The running sum is working fine but I'd like to add an extra data point that branches to show a specific number. Is that possible in qlik? Should I be using a different type of chart? I've drew something similar to what I am trying to achieve. I hope this clarifies what I am asking.

On my graph, that last data point shows $250, if that $-100 were to be approved. We don't mind manually change this data point but wanted to know can we even achieve this?

[Channa]

add second measure or try with reference line