Good morning. First, @ChrisAHeathcote gets the gold star for the day in using MovingSum() instead of TimeSum() as TimeSum() should not be used when the target is dimensionalized by Time. Second, @litterbarbie, I am not exactly sure what you are trying to solve, can you describe what you are after? If you are trying to get the max date for the current year, you can use this: MOVINGSUM(start, -Month + 1, 0, MAX)
If the MAX needs to reference the full year then you can not use zero as the end reference in the MOVINGSUM as this will move with the calculation. Using Zero will only bring the calculation upto the current period. While the start is -Month, end would be 12-Month if you are to capture the full 12 months for each period.
Yep, I was doing the calc from the beginning of the year to the current period of the time scale. And, if you wanted, you can change the summary to Max and then just reference the full year. Either way.