Has anyone done any testing to see if teams closer to a missions actual level give more bonus missions then high lvl teams blitzing them?

I'm interested because I have my normal team for clearing 12-5 and a speed team for clearing 1-3 / 2-1 and it seems that I get better bonus mission drop rates on the lower level team doing lower level missions then the high lvl team doing those same missions.

I have not done hard testing yet but the trend is becoming quite clear to me. It might just be an RNG streak tho.