Hello,
If there is a line between the 2 walls that means they are not coplanar
Align surfaces after having coplanar walls will be done by itself
If it's not you must check it is the same finishing material
And if it is the same composite wall you can pull it through the 2 levels to be sure to keep the alignement
Christophe - FRANCEArchicad Designer and Teacher
Archicad 15 to 27 FRA FULL
OS 11.6 Big Sur - MacBook Pro 2017 - 16Go RAM
"Quality is never an accident ; it's always the result of an intelligent effort" John Ruskin