[SOLVED] planification mode

Good morning,I am currently testing the different planning mode possibilities.I'm currently comparing "Fixed Duration" mode and "Duration Driven" modeThe starting postulate is a working day is configured in the software at 10 a.m.The resource has an FTE of 0.8 (tip because in the company some are regulated to 8 hours per day, others to 10 hours per day)When planning a fixed duration activity for 100 hours of assignment, 13 days of duration are necessary for the bar graph to remain green (13x10h =130h, 100/0.8 =125h) at 12 days (120h) of duration bar graph turns red, so far everything is normal.


   With the same starting assumptions, but only by changing the planning mode to “duration-driven” At 120 hours or 12 days of Duration, still 100 hours of assignment, here is the result:  At 130 hours or 13 days of Duration, still 100 hours of assignment, here is the result:
 

 At 150 hours or 15 days of Duration, still 100 hours of assignment, here is the result:   
At 170 hours or 17 days of Duration, still 100 hours of assignment, here is the result: 
Finally, at 200 hours, i.e. 20 days of Duration, still 100 hours of assignment, the bar graph is finally green, i.e. 60% of duration    So I don't really understand how time-driven works?
 
 

so in fact Duration driven make subbooking an surbooking...