Oh God, that wasn't easy! Great you tried and found out!
Glad to see I wasn't the only one that found this confusing

Thanks for making me look there again though! I kept trying
dev=0,1,2 because I proved it was working direct in the miner cfg file, who would've thought the AM parameter needed to be a different syntax?

I kept trying different variations in AM but they all had
"=" so even just trying
dev=0 would not work.