How to Calculate a Conditional Measure Before Slicer Filter is applied

[Anonymous]

I'm having trouble creating a measure that will behave in the following manner:

Existing Measures(#) > If the sum of that measure for each month is > 2000 then limit to 2000, else if < -2000 then limit to -2000 > Find the Sum based on the given date slicer and visual context

To my understanding, I need some way to calculate the of each month with the [NetRevenue wLimit] applied before it aggregates by Yearmonth. I'm not sure how to achieve this behavior. The examples below show I get the expected result when only one month is selected, but when I add multiple months in my date slicer the measure doesn't behave as desired. 

My guess is I need to use some type of iterator function(SUMX...), but I can't get anything to work. 

Expected Result: (Month Date Slicer)[June and July Selected]

SalesRepName	Net Revenue $	NetRevenue wLimit
Bob	200	200
Susan	-4000	-3000

What I getting instead [Month Date Slicer](June and July Selected)

SalesRepName	Net Revenue $	NetRevenue wLimit
Bob	200	200
Susan	-4000	-2000

If I expand the table to include year month the evaluated table looks like the following

SalesRepName (Column)	YearMonth(Column)	Net Revenue $ (Measure)	NetRevenue wLimit (Measure)
Bob	202106	-1	-1
Bob	202107	201	201
Susan	202106	-1000	-1000
Susan	202107	-3000	-2000

Measure Definitions:

Net Revenue $ = ([Ending Book] - [Starting Book])

*Note [Ending Book] and [Starting Book] are both calculated measures using the credits table

NetRevenue wLimit =
VAR MC =
    CALCULATE (
        SUM ( Credits[Amount] ),
        Credits[Credit Type] = "Management Change Add"
            || Credits[Credit Type] = "Management Change Add Term"
            || Credits[Credit Type] = "Management Change Drop Term"
            || Credits[Credit Type] = "Management Change Drop"
    )
RETURN
    IF ( MC > 2000, 2000, IF ( MC < -2000, -2000, MC ) )

Model:

Other information:

Salesrepname sourced from the historical salesroletable

Yearmonth is from the Dimension vw_Date table

[AlexisOlson · Accepted solution]

Yeah, the idea is to iterate at the level of granularity that your limit rules apply. It will look something like this:

Revenue with Limit =
SUMX (
    ADDCOLUMNS (
        SUMMARIZE (
            Credits,
            Credits[SalesRepName],
            vw_Date[YearMonth]
        ),
        "@MC", [MC Limit]
    ),
    [@MC]
)

[Anonymous]

Thank you @AlexisOlson. Could you explain what the "@" simple means and where I can learn more about iterator functions?

[AlexisOlson]

The @ symbol is just a naming convention for a temporary column. It's not an operator or special symbol. You could remove it and it wouldn't change how the measure works.