220V/15A getting to 100% SOC

I'm about to do my first trip of any real distance and since I work from home I have only every charged overnight to 80% SOC.

My home setup is 220V/15A (roughly 3.3kw) as I am running off a 20A circuit - this works great for my daily needs.

Planning for my departure time being at 100% SOC, I was wondering how much longer it would take going 80%->100% off AC. Turns out, at "low" current, it seems to be very uniform across the charging range.

Here are the numbers I got the last couple of days charging first night to 80%, then next day after getting back from the gym from 77%->100%

60-80% SOC took 5h 18m (5.3 hours) using 18kwh. 18kwh/5.3h = 3.4kw (3.77%/hour)
77-100% SOC took 6h 48m (6.8 hours) using 24kwh. 24kwh/6.8h = 3.5kw (3.38%/hour)

I was relieved to see on AC that the last 80->100% doesn't slow down line the DC fast chargers.

EDIT: to add the %SOC/hour