Summary Filed does not show in users roll

In this case i am working whit two tables, TIME CARDS and TASK 

one record in TASK have many record in TIMER CARDS.

I made a summary field in TASK that summarize  the filed "Total Hours" in the related records in TIME CARDS .

I made two reports to check the proper relationship, one count hours directly from TIME CARDS  and the second report shows the corresponding summary field "Total Hours" I described previously. 








I works perfect ,   even I added some field with the real started date and the last date hours were made in this task.

I have users with different rolls ( each one have only access to his people we grouper it by disciplines) .

And the same report is checked by me in user roll, this is what shows ;





The user roll have access to the hours from the table TIME CARDS, but he can not see the summary field "Total Hours" from TASK table.

Then I checked the set up of the roll, he has full access to all fields in TASK table , but does not show summary fields. WHY??



And I know he has access to the hours in the TIME CARD table because he can see it in the first report.


For more information here is the set up of the summary field "Total Hours" on TASK table.




Any idea??

Thanks.