Are you vaping 18-20mg on a sub ohm setup? If so I can't see how you're not getting more nic out of that than a pod.
Put it this way, I vape 7 ml of 6mg/ml a day, or 42mg of nicotine. A Juul user uses 0.75 ml a day (one pod) at 50 mg/ml = 38 mg. The difference is the size of the puff, it's a tiny little puff you get off a Juul especially when compared to my cloud mods.
A couple of my setups are sub ohm, but I can do lung hits on my pod systems (one is a Smok Novo, and another is a hacked nJoy Ace) and I go through way more than .75ml in them when I use them. The Smok holds 2ml and I need to constantly refill it, so I mainly use the pods just for stealth vaping because filling is a PITA. I am guessing the nJoy probably holds about the same, that one is even harder to fill because it is not meant to be refilled so you need to take it apart.
I understand that cloud chuckers burn more juice, but much of that is wasted on exhale. And I tend to hold my stealth hits till there is pretty much nothing left and exhale in my shirt. Maybe that's why I do not notice a difference, but I do burn through a ton of liquid with the pods.