Problems with formula for creating cumulative counts for a Task Burn-Up Chart

[DTaraboletti]

This appears to be a common question within this board and elsewhere on the internet...but having reviewed multiple posts, I'm still unable to do a calculation for cummulative task values for use in a burn-up chart.   

I've used the following link as a primary reference...

https://www.youtube.com/watch?v=dMJLypl5HJg

The forumla referenced is shown below and appears at 4:08 within the video

And have tried to duplicate this formula within Power BI Desktop as noted below.   

As presented within the screenshot... I have a prepared a table that includes weekly counts of planned and baseline finish counts.   The table includes all dates (Column 2) ...irrespective of whether or not tasks are planned for that week (reference 0 values in columns 3 & 4).

Column 1 and the formula bar represent my attempts at creating a cummulative count of Planned tasks (column 3 above).   

The (desired) resulting table should look like the Excel generated version below...with the yellow columns being the desired, calculated columns.

Any help would be greatly appreciated.

Thanks in advance.

[DTaraboletti · Accepted solution]

Found the solution....

Cummulative Planned Finished Task Count = CALCULATE(sum('Project Schedule Burn-Up Weekly Count'[Weekly Planned Finish Task Count]), FILTER (ALLSELECTED('Project Schedule Burn-Up Weekly Count'[Period Week End]),'Project Schedule Burn-Up Weekly Count'[Period Week End] <= MAX('Project Schedule Burn-Up Weekly Count'[Period Week End])))

[DTaraboletti]

The formula that i'm currently using in Power BI Desktop (shown above in screenshot) is provided before for clarity and for easier viewing:

Cummulative Planned Finished Task Count = CALCULATE(SUM('Project Schedule Burn-Up Weekly Count'[Weekly Planned Finish Task Count]),'Project Schedule Burn-Up Weekly Count'[Period Week End] <= MAX('Project Schedule Burn-Up Weekly Count'[Period Week End]))