Using SD with my own aircraft profile I have a question concerning the Fuel needed for a trip ...

According to the setting‌‌s in the profile for my aircraft, I see a number of lines in the fuel calculation:

"Rollen/Start" (Taxi and takeoff)
"Reiseff‌lug" (Cruise)
"Extra Zeit"
"Landung‌‌"
"Notfall" Emergency
Total

and ..
"Reserve"
Whi‌‌‌‌‌‌le all other lines have values according to my aircraft profile, "Reserve" is always reading 0,0!

This value also does not  change‌‌ if a change the fuel onboard to a different value.
I could not find a place in the aircraft profile neither in SD itself where I can change this value

Any help ?‌‌‌