Countax with selectedvalue expresion returns Zero

Hi

I started with this thread wondering how to solve the issue. From there I got to a solution with a DAX meassure but it's not working for the totals.

I got this table:

It records whos is recording in a studio (Actor) and what is recording (content type).

They can record content only for them (A or B) or content for both (AB).

The content for both (AB) can be recorded separately or together (same time and date)

The problem is when they record together, the recording session adds the double of time. i.e. the session of the 04/01/2021 A and B are recording together in a 2 hours session length, but the sum will acount it as 4 hours of recording.

My approach is concatenat the ID column = [Content type] & [Date] & [time start] & [time end]

This ID will be repeated by the people recording togehter (same time and date), therefore I wrote this Measure:

both adjst = SUMX ( Data, Data[Total hours] / COUNTAX ( Data, SELECTEDVALUE ( Data[ID] ) ) ) 

It works as expected

Just the date 04/01/2021 is summirezed and divided by the count of IDs... the problem is that I need the total as well.

I understand the the total returns infinity because theres no selectedvalue and returns Zero, so the division is infinity, but I don't know other way to do this. It could work as well in a DAX added column but thhis way selectedvalue won't work.

I tried using and IF:

both adjst 2 =
IF (
    ISBLANK ( SELECTEDVALUE ( Data[ID] ) ),
    SUMX ( Data, Data[Total hours] / COUNTA ( Data[ID] ) ),
    SUMX ( Data, Data[Total hours] / COUNTAX ( Data, SELECTEDVALUE ( Data[ID] ) ) )
)

but this doesn't work for the total

I tried CALCULATE and the expresion above with an filtering thinking it would be executed row by row...but the result is the same.

I'm thinking a dax column would do the work but no clue how to do it. A new column with the fixed values for Total hours, meaning Total hours divided by the count of The ID appear in the table.

Any idea will be welcome 🙂

thanks

Pepe