Richard Bong
Space Marshal
It is temporary as they figure out how far they want each size and type of ship to go on a tank of gas. Once they have the basics down, they will adjust the individual drives and ships. (Or at least that is how I would do it. One parameter at a time.) In the past they have changed multiple parameters at once then wondered what went wrong.
Granted this nonsense should have been figured out about a decade ago, but this is CIG.