SDP MSP 9204 - Worklog time spent always automatically filled

SDP MSP 9204 - Worklog time spent always automatically filled

Good afternoon,

We are using heavily the "work logs" inside the SDP MSP to track our people's work. The goal is to correctly put a time spent on a task, e.g. 8 hours. But these 8 hours can be spent between 8:30 and 17:30, including 1 hour of lunch time. 
If we try to set the start and end time of the work log like this, it calculates automatically the time spent to 9 hours, which is not correct in our case.

Is there any possibility to have the begin and end date fully independent from the time spent?

Thank you for your assistance!
Sebastian