bro he still didn't surpass Luffy's last pre-timeskip bounty (400 million)
See it's like.
luffy first bounty - 30 mil , zoro - no bounty
luffy second bounty - 100 mil , zoro - 60 mil (Surpassed luffy previous bounty)
luffy third bounty - 300 mil , zoro - 120 mil (Surpassed luffy previous bounty)
Luffy 4th bounty (marineford) - 400 mil ,(zoro was not there)
Luffy 5 th bounty - 500 mil , zoro - 320 mil (surpassed luffy previous bounty raise bounty when whole crew bounty was increased)
luffy 6th bounty - 1.5 B , Again zoro not present.
luffy 7 th bounty - 3 B , Probably should more than 1.5 or around it.