I understand your math, and while the Health New Zealand studies show less nicotine from e-smoking, I'm not entirely personally convinced. I'm pretty sure I've INCREASED my blood nicotine by e-smoking and snusing. Here are two relevant paragraphs from a medical article I read today:
"The nicotine content in cigarettes varies widely depending upon brand, but usually averages around 1mg per cigarette. The actual amount absorbed upon smoking will depend upon how the cigarette is smoked, as well as the presence and amount of other added ingredients. Compared to other delivery systems, nicotine levels from cigarettes peak within minutes and fall shortly thereafter. Because the half-life of nicotine is around 2 hours, those who smoke more than one cigarette over the course of a day will demonstrate accumulated nicotine levels in their plasma.
"It should be noted that the highly addictive quality of cigarettes lies not within its nicotine content, but rather its nicotine pharmacokinetics. Cigarettes provide an immediate jolt of nicotine to the CNS (central nervous system), resulting in almost instant gratification. Delaying nicotine gratification with the use of slower delivery mechanisms should aid minimizing addictive potential."
Does this not mean we could indeed "step down" nicotine levels to get off nicotine altogether at some point? Some might want to try that claim from various manufacturers. Let us know if it works.