Monthly Running Total, Extra Values "Leaking Through"

[Brotedo]

Hello,

I have yearly sales running total that begins in the current month and runs 12 months. The cumulative totals seem to be working, but for some reason some extra amounts (~1% to ~10% depending on category) are "leaking through" to the column subtotals.

The first row is a target that just accrues a static amount each month, but the second row is a cumulative total of sales. The July 2023 number should be the same as the total, but it's not.

Here is my cumulative sum measure:

Rolling12 = 
VAR DateMax =
    MAX ( 'Plan'[DateDiff] )
RETURN
    SUMX (
        CALCULATETABLE (
            'Plan',
            REMOVEFILTERS ( 'Plan' ),
            VALUES ( 'Plan'[Id] ),
            'Plan'[DateDiff] <= DateMax,'Plan'[DateDiff]>=1, 
        ),
        [12 Month]
    ) 

DateDiff is just this

DateDiff = DATEDIFF(today(), 'Plan'[date], MONTH)+1

I know there are tons of possibilites here for what could be causing this, and there are too many details with my datasets and relationships to describe each one, so I guess I'm looking for general answers here - what kinds of issues could be causing this? 

[daXtreme]

Hi @Brotedo 

If you have bi-dir relationships and - God forbid - many-to-many... then you'll have to either change the model to be correct and simpler (meaning star-schema without any exotic relationships), or... you'll have a very hard time troubleshooting. Some relationships behave very unintuitively and before you use them, you should really know all the issues that can arise. Also, if your model is complex, I don't think you'll get a general advice that will help you fix the issue. But - as always - I might be wrong and there'll be somebody that will manage this.