SUMX with FIRSTNONBLANK Values, incorrect totals

[cdawidow2]

Hi guys,  I created a measure to track historical values of specific opportunities using FIRSTNONBLANK.  This result turns out okay for each individual opportunity but for the totals, which I want to include all opportunities, the values are not summing correctly.  

Below is the measure I use to retrieve my historic values.  

HISTORICAL AMOUNT = VAR X = calculate(MAXX(VALUES('Opportunity History'[SystemModstamp]),'Opportunity History'[SystemModstamp]),USERELATIONSHIP('DATE'[Date],'Opportunity History'[CreatedDate]))

RETURN

CALCULATE(FIRSTNONBLANK('Opportunity History'[Amount],'Opportunity History'[Amount]),'Opportunity History'[SystemModstamp]=X,USERELATIONSHIP('DATE'[Date],'Opportunity History'[CreatedDate]))

But I am having trouble with the total value - I think I should use SUMX but even when I do the values do not total correctly. 

Any help would be appreciated.   I have also included my schema below. 

[Tanushree_Kapse]

Hi @cdawidow2 ,

Try this meausre:

FixedTotal= SUMX(VALUES(Table[OPPORTUNITY]),[HISTORICAL AMOUNT])

Mark this as a solution, if I answered your question. Kudos are always appreciated.

Thanks