Evaluating Email CPA: Insights from 30 Days of Daily Newsletters

I'm 30 days into my daily newsletter (m - f), and have acquired 1000+ USA based leads via paid ads.

I have the following segments set to exclude

No opens in first week (0/5) (30%)

My average cost per lead (CPL) is $0.66, I am marking a +30% cost to this due to the 30%^

Therefore I am considering my CPL as $0.86

Open Rate for the newsletter is averaging 40%

Is this the right way to evaluate CPL? I hear brands like Milk Road / Morning Brew say $1 - $2 per lead as average CPL, but is this an engaged lead or just any lead?