Running total with Blank values

Hello All,

I am trying to calcualte running total with the columns coming from three different tables.

First Table - Calender - Using Date Column

2nd Table - Clouser Table - using Matching Variable Column, MIS Column

3rd table - VOLUME - using VOLUME column

Data Modelling

I have created a measure using below formula which is using matching variable from CLOUSER table, VOLUME from VOLUME table.

_IPTV = 
DIVIDE(COUNT('GM Clouser'[Matching_Variable]),sum([Volume]),0)*1000+0

the sample data looks as below where year, month from Calendar table, MIS, Matchin variable from CLOUSER table, VOLUME from VOLUME table.

Please see the below link where you can find the csv data.

data.csv

**Please note that the data is coming from three different table here**

I have written the dax code to get the running total as below.

Running Total IPTV = 
 VAR MaxDate = max('CalendarTable'[Date])
 RETURN
CALCULATE (SUMX(CalendarTable,DIVIDE(COUNT('GM Clouser'[Matching_Variable]),sum([Volume]),0)*1000+0), 
    FILTER( ALLSELECTED( 'CalendarTable'), 'CalendarTable'[Date] <= MaxDate),
    FILTER(ALLSELECTED('GM Clouser'),'GM Clouser'[MIS] = MAX ( 'GM Clouser'[MIS] ))
)

I values are coming right but for the blank values of matching variable where IPTV values are 0, it is returning blank in running total 

the running total values should get carryforward if it is blank.

Can anyone please guide me to correct the same.

Thanks,

Mohan V.