I don't see a problem personally, not something I'd go complaining to the dealer about.
I expect you'll find the man. sum. time field was removed (or added, doesn't matter which) because that, and the timezone field, have exactly the same result - manually offsetting your clock from UTC/GPS-time, it's not a setting which enables an automatic daylight savings switch now or in the future. it does one fixed thing - advance the clock by 1 hour when it's 'on' and not when it's 'off'.
Set the timezone to +1 hour and move on.