When I first started, I was still grabbing a cigarette once a day and couldn't figure out why so I did an internet search and found a study that they did on the absorption of nicotine in the body from an e-cig vs a regular cigarette. I'm too lazy to look for it right now, but basically they measured the amount of nicotine in the blood after smoking and after vaping.
I'm doing this from memory so don't quote me on this, but if I remember right, the amount of nicotine absorbed from a cigarette is 1/10 of the amount in the cigarette, and the amount from vaping is 1/10 of that. So if you had a cigarette with 18 mg of nicotine, your body only absorbs 1.8 mg of the nicotine. If you vaped 18 mg nicotine juice, your body only absorbs 0.18 mg of the nicotine.
So, the answer would be, yes, you do need to increase the amount of nicotine you vape to compensate for what's not getting absorbed.
My problem now is that when I get super-stressed (like a month ago when my 15 year old son came home with a tattoo or yesterday when he outright refused to take out a septum piercing that I told him he couldn't have) I reach for a ciggie. It has nothing to do with the nicotine, but more with the calming effect of holding that ciggie in hand and taking a drag. After decades of dealing with stress that way, it's hard to break that habit.