I thought an update to this is relevant, all the above is true and my car is still running fine, that said I have been informed that an AGM battery should not be charged with the recondition mode as it could cause damage.This may be useful to some, I purchased a 2021 GLC300 from Blackburn around a 5 hour drive from me, on collection the car had completed 2300 miles as it was a lockdown car.
I drove the car home so it should have had a good charge on arriving home around 5 days later I had a low battery message but despite taking the car on a few runs I still had the warnings.
I put the car on charge using a CTEK MXS 5.0 charger but a few days later the warning returned, as the car is still under warranty I was not too worried but rather than take the car in I put the car on charge again but ran a recondition programme with the charger, this took around a day and a half to complete, that was several months ago and I have not had an issue since.
Robin
The CTEK manual actually shows the modes available and does show a recondition mode with AGM batteries so it seemed ok to me but an email to support at CTEK asking received the reply do not use this mode?