Get the Difference of the Selected Category Value and the Previous Value of the Selected Category

[EvanGetsItDone]

Hi,

I have scenario here wherein I need to get the difference between the value of the selected Snapshot Category and the previous value of the selected Snapshot Category. In my current progress, I am able to get the difference between both but only because the categories are selected beside. here's a screenshot for reference:

Let us take and look at August 2023 Snapshot Category for example. so PreviousValue - SalesValue (the Selected Value, since it has the higher sequence selected.) 
the Test_Difference measure result is 5,676,388 which is correct. 

now the problem is, if I remove the July from the snapshot category slicer:

It is just basically still June 2023 minus August 2023.
in my case. What's expected is in this example, is when I remove July, then August 2023 Test_Difference measure should now be June 2023 minus August 2023

I would appreciate you help a lot guys. Been through this for weeks.
Let me know if you need more details. 

Thanks!

[miTutorials]

Have you tried Visual Calc ? They solve this problem. See the tutorial below. Watch from 7:40 onwards..

🚀 NEW FEATURE : Magic of Visual Calculations in Power BI | MiTutorials (youtube.com)

[EvanGetsItDone]

Unfortunately, this is a new feature and I couldn't update the power bi desktop I am using due to limitations, since we are using it in a remote desktop. This is a good addition to knowledge though and will be using this in the future. But for now, I am afraid that this wouldn't be an option in my current scenario.

thanks for taking the time to help out sir!