I think this is the tour you are asking about (
https://www.adventuresbydisney.com/north-america/hollywood-disneyland-tour/daily-itinerary/)
These are guesses based on pure speculation and no insider knowledege/information:
Possibility 1) They alter the Studios/Archive tour so that you spend more time at Walt Disney Studios and Archives.
Possibility 2) They start the Studios/Archive tour later in the day so that the guests arrive at the resort the same time as before.
Possibility 3) They start the Studios/Archive tour at the same time, the length of the tour does not change, and guests arrive at
Disneyland resort earlier in the day.
I am planning to do this tour next year so if I hear anything official, I will post here to let you know.