DAX Using a Measure in formula produces a blank and can't see why

I have cross posted this question with MR. Excel ;

https://www.mrexcel.com/board/threads/dax-measure-used-in-formula-produces-blank-but-not-when-variable.1220151/

Hi, i have the following measure formula in DAX power pivot to retrieve the previous unit value, I have attached the workbook with examples of each.

so first to get the previous date ;

MAXX(
FILTER(ALL(Table1[Date]),Table1[Date] < IF(HASONEVALUE(Table1[Date]),VALUES(Table1[Date]) ) ),Table1[Date])

Then ;

Previous Unit :=
CALCULATE (
    [Tsales],
    FILTER (
        ALL ( Table1[Date] ),
        Table1[Date]
            = MAXX (
                FILTER (
                    ALL ( Table1[Date] ),
                    Table1[Date] < IF ( HASONEVALUE ( Table1[Date] ), VALUES ( Table1[Date] ) )
                ),
                Table1[Date]
            )
    )
)

So I thought I should be able to use the first measure inside the second,

   CALCULATE([Tsales],FILTER(ALL(Table1[Date]),Table1[Date] =  [Previous Date] ) )

But this just return a blank? Any explanations as to why?