How to subtract time

Hi,

I'm fairly new to Power Bi and would appreciate assisstance on the following:

I am trying to work out the difference between planned and actual time.

As you can see in image below :

• SECOND ROW = 40 minutes
• FIRST ROW = -15 minutes

My issue is with the first row. Due to it being a negative, it comes up as 'error'.

I don't need it to show the negative symbol but difference in HH:MM format

The table above is one a I created on Power Bi desktop

Is there a way I can work around this?

Note: I do have excel sheet that shows exactly what I need however when I upload, all formulas mess up. Can I keep my formulas?

Thanks Heaps!