Calculate MOM based on DateKey

Hi All,

I have removed Timestamp (Date) columns and using DateKeys in Fact Tables .  I need to  update few measures from Date to  DateKey. I have below measure (MOM) but facing issue while using DateKey. Is there any workaround (( I need to convert yyyyMMdd to Date while adding to DateAdd Function)

[Total Sales] = CAlCULATE(SUM('FactSales'[Sales]))
MOM Sales : (CALCULATE([Total Sales],ALL('Is Latest'),TREATAS(VALUES('Is Latest'[FactSalesLatestDateKey]),'Date'[DateKey]))/(CALCULATE([Total Sales],ALL('Is Latest'),DATEADD(TREATAS(VALUES('Is Latest'[FactSalesLatestDateKey]),'Date'[DateKey]),-1,MONTH))))-1

Note: We keep 2 months daily data and remaining months as monhtly data ( aggregate daily data to single day( last day of month)) in FactSales

FactSales:

Date: Marked as Date Table ( Date Column as UniqueIdentifier)

Is Latest: this Table tracks Latest datekey in fact tables

Relationships:

FactSales * (DateKey) --> 1 Date (DateKey)

FactSales * (DateKey) --> IsLatest(FactSalesLatestDateKey)

Thanks,

Abhiram