Matrix fIltering issue

Anonymous yes it is a relationship issue. you need to create an active relationship on cost element between your sheet5 and sap data.  since in your visual you are showing the data at cost element level but in the abence of any active relationship between cost element between these two tables, entire value is appearing against each cost element. 

I can see there is an inactive relationship between these two tables. in that case, you can use this inactive relationship in your measure to calc correct estimatd value. You can create a measure like below. Please correct the syntex as per the actual names of fields in the data.

estimates = calculate(sum(estimates),userelationship(sap_data[cost element], sheet5[cost element])