Can't seem to apply SAMEPERIODLASTYEAR correctly

[spartan27244]

The following calculation gives me a value called PMPM on my report correctly, and displays the correct amounts.

PMPM = Sum(Paid) / Sum(MM)

to get the previous years I was attempting

PMPM-PY = Calculate(Sum(Paid) / Sum(MM), SAMEPPERIODLASTYEAR(Dates[Date]))

Where Dates is my Marked Date table, however this does not yield any results. The PMPM calculation is cleary confined to the time period on the report, currently (10/1/2019 - 9/20/2020) so I am uncertain of why the previous year would not be able to infer this.

[Fowmy]

@spartan27244 

Did not quite got it, anyhow , can you try this modified version:

PMPM-PY = 
DIVIDE(
    Sum(Table[Paid]),
    Calculate(
        Sum(Table[Paid]),SAMEPERIODLASTYEAR(Dates[Date])
    )
)

[spartan27244]

To try and break this down a bit to a more simpler calculation to get the flow...

A simple sum of a Base Table Amount "MedPlanPaid" is shown on the left of the grid, next to it is a measure that calculates the exact same value as Sum(MedPlanPaid), The problem in this context is how to reference  the previous year. So in the grid the PY calculation (far right) should show the same value as the previous row (i.e. previous year). If I can do that, then I can expound on the calculation to get where I want to go. Here is a snapshot of the visual 

And a snippet of the model showing the replation show between report periods, the date table and the claims data