How to ignore filtering on selected column - equivalent of Power BI's Calculate( [] ; All( [] ))

Question

I would like to create a measure [Ultimate case count] that would disregard any filtered out values on the diemension ReasonID.

But still be sesitive to othere filteres (FInancialName and ImportDate). I Have been trying with FIXED and EXCLUDE but can't get it to work...

Measure [CaseCount] is just a sum() and diff is [Ultimate case count] - [CaseCount]