Thank you for the help @Zen_Turtle I changed my number to 8 mins (480 seconds). I also realized that I had a couple extra workouts on Strava that I forgot to delete when I was dual recording (duh!). I pulled those off and the eFTP is now much closer to what I think it should be.
Alright – thank you for the further explanations.
In fact, thinking about that workout and the fact that eFTP was based on a 7 min “intervals” on a mixed hill (3 steeps with 2 intermittent flats/slight downhills) and the fact that I even had to slow down for a car more or less at the beginning, I decided to bump up my (estimated) FTP a bit (from 280 to 300) and to put in the W’ from i.icu (20.5 kJ). That leads to a W’bal close to 0 for that climb (and positive for the rest of the ride). Maybe I keep guesstimating FTP at that value for today and see how that works for future rides… I am not sure I can hold ~315 W for 20 min, but then I never tried. Maybe I should RSN;-)
Is that a reasonable guess for a start?
Here’s a graph of that interval:
20.5 kJ sounds like a valid measure.