Hey Prongs,
after running several tests with Range 10 vs Range 150 and different levels and logging them in a spreadsheet I came to the conclusion that theres no difference wether you go 10 or 150 Systems. The only difference is that the time for finishing them got raised. Loot value was untouched. In my sample size (roughly 90 Missions on 10 and 90 Missions on 150) the result of doing them all was that 10 Systems is better than 150 both in MetalUnits vs Lithium Usage aswell as time.
This might be a bug becasue the ingame tooltip indicates better results the further you go.
Best regards,
Bauws