dfk41 I’d measure what you can see.
So start the timer when you hit the ‘On’ switch.
If you wanted you could also check when the last water is dispensed from the nozzle, you’ll probably hear it though.
Note when the stream from the cone slows to drips (record this time). Then leave in place another 30-40s.
I don’t see how the target of 3-4 min is possible if it takes 3:40 to 4:00 just to dispense all the brew water into the filter cone. Where does this target time come from?