Report "Detailed Work - monthly" with an wierd total

Hello,

I was analysing some real work on a project and I realised the total of the "Detailed Work -monthly" doesn't seem right:


And when I look into the report "Detailed work per resource - monthly" with exactly the same parameters, I get even a different value (by ressource and globally).


Do you have any idea why?
I can I be sure of my calculations?

Thank you for your help.

Regards,
MCanuto

P.S. : version 8.6.3

I have the same problem.
The detailed reports seems to have weird results.
In timesheet : Adrien worked 9,2 hours on WP9 (subtask of BIPVBOOST project) during week 26
1 day = 7,6 hours

In detailed weekly report : 
Projector has calculated that he worked 2,34 days instead of 1,21 days (9,2/7,6)

How is that possible?

Proj version : 9.2.0

EDIT :
After some test, i have the impression that Projeqtor keeps in mind all the changes. for instance, if one day I work 7,6 hours on a project. the detailed report will be ok and tells me I worked 1 day. If I make a change and tell him it was only 3,8 hours, the result in the detailed work will be 11,4 hours instead of 3,8.
EDIT 2 :
I see also that the report Detailed work for a resource - per year seems to be correct. So it is only in the "between two dates" reports that there seems to be  something wrong.