Tricky, no amps, low pay out on the 100's....I'd like to see someone really crunch the number certainly not as sure now

I've done some stat on the SGQ 80 and Manyu Spirit Quest 80:

Manyu Spirit Quest 80 stamina:
28 runs
Lv100 : 14 => 0.5/run
Lv20 : 66 => 2.4/run
Lv5 : 31 => 1.1/run

Secret Garden Quest 80 stamina:
31 runs
Lv100 : 44 => 1.4/run
Lv20 : 66 => 2.1/run
Lv5 : 0 => 0/run

This was before the "bonus" in the manyu quest.

As a side note, I have ~55% of chance to get the center chest of SGQ.