YTD Changes

I have an issue with a YTD that keeps changing. 

I measure a delivery performance from an external warehouse. Including in the model i have a YTD. But it keeps changing. 

I wrote this formula 

Service Level YTD :=CALCULATE([SL];DATESYTD('Calendar'[Date])

But if i chose to look at the service level in January, the YTD changes off course as we are now in Mar. 

So i therefor made:

Service level YTD :=CALCULATE([SL];ALL('Calendar'[Date]);DATESYTD('Calendar'[Date]))

But the Service Level YTD still changes, so apparently it doesn't overwrite my date filter. ?

I am btw doing this in PowerPivot in an Excel workbook for now, i will eventually turn it into a PowerBi report, I just haven't gotten around to that yet :)