Calculate running total based on initial sum

Hi. I would like to calculate the projected net outstanding amount which is based on the current outstanding.

In Week 1, the 'Net outstanding' is calculated by substracting the 'Net risk' from the 'Current outstanding'. However, in Week 2, the 'Net risk' should be subtracted from the previous 'Net outstanding' (hence from Week 1) and not from the 'Current outstanding'.

I am looking for the below output.

Note: I have a live connection to an Azure Analysis Service database, so I am not able to add columns in the editor nor query.