Delta Funnel

Hi, hamadani 

As a workaround, you can  try the following steps to visulaise the delta funnel.

1. add a summarize table:
calculated table:

Table 2 = SUMMARIZE('Table','Table'[Page Name],"No.Unique Customers",DISTINCTCOUNT('Table'[Customer ID]))

calculatd column:

Rank = RANKX(ALLSELECTED('Table 2'),'Table 2'[No.Unique Customers],,DESC,Dense) 

Rankvalue = 
RANKX (
    'Table 2',
    'Table 2'[Rank]
        + RANKX ( 'Table 2', 'Table 2'[Page Name],, ASC, DENSE )
            / CALCULATE ( COUNTROWS ( 'Table 2' ), ALLSELECTED () ),
    ,
    ASC,
    DENSE
)

No.Dropped Customers = 
VAR a = 'Table 2'[No.Unique Customers]
VAR b =
    CALCULATE (
        MAX ( 'Table 2'[No.Unique Customers] ),
        FILTER (
            'Table 2',
            'Table 2'[Rankvalue]
                = EARLIER ( 'Table 2'[Rankvalue] ) - 1
        )
    )
RETURN
    IF ( ISBLANK ( b ), BLANK (), b - a )

2. consider using custom tooltip page to show the Dropped Customers.
Result:

Best Regards,
Community Support Team _ Eason