DAX Calculation - Find value based on day (relative)

hi edgarMunoz ,

Not sure if i fully get you, supposing you have a reference date slicer fed with a disconnected dates table, you may try to write the measure like this:

Measure = 
SUMX(
    VALUES(balance[AccountNumber]),
    CALCULATE(
        MAXX(
            TOPN(1, FILTER(balance, balance[RecordDate]<=MAX(dates[Date])), balance[RecordDate]),
            balance[Balance]
        )
    )
)

it works like:

Please find more in the attachment.