DAX power pivot Cumulative averages

Hi,

I want to a cumulative average by date and have come up with tow formulas both correct in their own way, but I think one is more efficient but doesn't give tithe answer I wanted, the other does but been told it'Not a good way of doing calculations,

the two are ;

 Rolling Average :=

CALCULATE (
    [AvSales],
    FILTER ( ALL ( Table1[Date] ), Table1[Date] <= MAX ( Table1[Date] ) )
)

This will give an average of all the dates on which sales were made, then,

Rolling Average Aggregated Dates :=
AVERAGEX (
    FILTER ( ALL ( Table1[Date] ), Table1[Date] <= MAX ( Table1[Date] ) ),
    [Tsales]
)

this gives an average of the aggregated dates, so in you have ten 10/01/2020 it will still only count as one, but as said have been told that this is not a good way of doing a cumulative total so replacing AVERAGEX with SUMX.
Is there a way to use the first measure but make it only count each date once? Workbook attached.

Richard.