How to achieve this: Multi-Rows with same unique ID

First, some inconsistencies that may need clarification.

1. You do actually have repeat refs in the provided example bonus table (e.g. 30243789-90). 
2. Your output table seems to be inconsistently pushing bonuses to first date (e.g. pushing M03 bonus to M01 for 30243763-140, but keeping M02 bonus in M02 row for 30243789-90). Is the output table incorrect, or does more of the logic need to be articulated on why we are summarizing at earliest date row for some refs but not others?

With that said, I came up with two measures (for w/o totals and w/ totals) that should work assuming the following:

1. You want everything summarized on every Ref#'s earliest date row
2. There is no relationship set up between the tables.
   Note, if repeat Ref# are in both tables, to set up a relationship, we would either need to create a relationship on a calculated column added to each table that factors in Ref# + Date or Month, M:M relationship (with I assume filtering direction from TX Table --> Bonus Table), or a dinstict Ref# table in between the two so we get M:1:M relationship

I've provided two measures, almost identical, except one has an outside SUMX to enable subtotals/totals:

Eligible amount for Bonus ($) = 
VAR CurDate = SELECTEDVALUE( 'TX Table'[Date] )
VAR CurRef = SELECTEDVALUE( 'TX Table'[Ref#] )
VAR RefRankTable = 
CALCULATETABLE( 
    VALUES( 'TX Table'[Date] ), 
    REMOVEFILTERS('TX Table' ), 
    VALUES('TX Table'[Ref#] ) 
)
VAR RefRank = RANKX( RefRankTable, 'TX Table'[Date], CurDate, ASC )
VAR Amount = 
IF( 
    RefRank = 1, 
    CALCULATE( 
        SUM('Bonus Table'[Eligible amount for Bonus ($)]), 
        TREATAS( { CurRef },'Bonus Table'[Ref#] ) 
    ),
    0 
)
RETURN
Amount


Eligible amount for Bonus ($) w/ Total = 
SUMX(
    'TX Table',
    VAR CurDate = 'TX Table'[Date] 
    VAR CurRef = 'TX Table'[Ref#] 
    VAR RefRankTable = 
    CALCULATETABLE( 
        VALUES( 'TX Table'[Date] ), 
        REMOVEFILTERS('TX Table' ), 
        VALUES('TX Table'[Ref#] ) 
    )
    VAR RefRank = RANKX( RefRankTable, 'TX Table'[Date], CurDate, ASC )
    VAR Amount = 
    IF( 
        RefRank = 1, 
        CALCULATE( 
            SUM('Bonus Table'[Eligible amount for Bonus ($)]), 
            TREATAS( { CurRef },'Bonus Table'[Ref#] ) 
        ), 
        0 
    )
    RETURN
    Amount
)

 Output: