Format causing measure to return blank.

I'm using a measure with disconnected slicers to return a value depending on how the user interacts with the report. They can choose to view values as values or percentages, and can choose from 3 measures.

I have 6 measures to handle the different cases, and a final measure that handles the final display based on the switch. Mathematically everything is working fine, however when I try to format the percentage display with the FORMAT() function, I only get blanks returned.

Here's an example code of one of the base measures:

Histogram Count = 
VAR BucketFloor =
    MIN ( DimHistogramBuckets[Floor] )
VAR BucketCeiling =
    MIN ( DimHistogramBuckets[Ceiling] )
RETURN
    COUNTROWS (
        FILTER (
            ADDCOLUMNS (
                VALUES ( Dim[Group] ),
                "Pct Change From Previous Year", [Percent Change From Previous Year Rate]
            ),
            SWITCH (
                TRUE (),
                [Pct Change From Previous Year] = 0, [Pct Change From Previous Year] = BucketFloor
                    && [Pct Change From Previous Year] = BucketCeiling,
                [Pct Change From Previous Year] > 0, [Pct Change From Previous Year] > BucketFloor
                    && [Pct Change From Previous Year] <= BucketCeiling,
                [Pct Change From Previous Year] < 0, [Pct Change From Previous Year] >= BucketFloor
                    && [Pct Change From Previous Year] < BucketCeiling
            )
        )
    )

Here is the final measure that controls the displayed measure on the report:

Histogram Selected Measure = 
//This measure returns a measure to be displayed in the histogram depending on switch options in the report.
VAR DisplayID =
    MIN ( DimHistogramDisplaySelect[ID] )
VAR MeasureID =
    MIN ( DimHistogramMeasureSelect[ID] )
RETURN
    SWITCH (
        DisplayID,
        1, SWITCH (
            MeasureID,
            1, [Histogram Count],
            2, [Histogram IE],
            3, [Histogram Premium]
        ),
        2, SWITCH (
            MeasureID,
            1, [Histogram Count Percent],
            2, [Histogram IE Percent],
            3, [Histogram Premium Percent]
        )
    )

In the code just above, in the case where DisplayID = 2, this is working just fine, but if I try to alter the code like so:

MeasureID,
            1, FORMAT ( [Histogram Count Percent], "0.0%" ),
            2, FORMAT ( [Histogram IE Percent], "0.0%" ),
            3, FORMAT ( [Histogram Premium Percent], "0.0%" )

The measure now returns blanks instead of the appropriate values.

I have used this method before, so I cannot for the life of me figure out why this is happening. If anyone could be assistance, help would be greatly appreciated.