Hello nonco,
Do you try to use these option step by step you was modeling your stair ?
I think you should begin your stair with the second step (and then pull it to you original "start").
Then stand by your stair modeling each time you have to change these options above.
Mery Xmas !
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