Leveling Question

Maya level 40ish. Just got back to my friends at Sanctuary after the city blasted off. Did 2 missions in the Dust. Clan Wars was at level 40. The Good the bad the Mordecai was at level 36. What gives? Why the big difference? I was able to get a level 42 Slagga from the hillbillies after some work, but only level 36 Lyudas from Boot Hill? I dont get it.