You are not selecting "minutes of fuel" per se.
You are selecting % of fuel in tank (but instead of %, you can see how long your aircraft will stay in air with specific amount of fuel in tank).
Think on it as 20%, 40% 60%, 80% and 100%
More options simply do not change a lot and will create complications (my wild guess).
How it is superior?
As I said earlier - you are selecting %
Lower amount of fuel you can take = AFAIK lower amount of fuel aircraft could take to take off and fly in normal conditions.
More complicated system =/= superior.
More complicated system = more complicated interface + more options for bugs.
And for what? So you can take 22min. of fuel instead of minimum 20?
I guess someone already submitted similar suggestions, but if not, feel free to do so in Suggestion Section
Well, to suggest something you would like to see in game you need to submit it to suggestion section
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