Optimised Charging Completion Time

iPhone SE3, iOS 16.6.

I've just completed set-up of Optimised Charging (OC). During set-up, the phone was connected to the charger every night at about 9.30 pm and disconnected every morning at 6.00 am. I expected this to mean that OC would aim to complete charging from the 80% overnight float charge to 100% just before 6.00 am. That doesn't seem to be the case. On my lock screen, there is a message saying that scheduled charge finish is 2.30 am., 3.5 hours before wake-up time.

Will the phone gradually 'learn' that wake-up time is 6.00 am not 2.30 am or is this apparently arbitrary completion time of 2.30 am permanent now? Or should I try to set-up OC again by disconnecting in the morning around 8.30 am in the hope of achieving something closer to 6.00 am?

Available information from Apple re. OC is quite poor, IMO.