Well, I would not call this a huge bug.
Unfortunately, I don't think you can change that because it is hard-coded into the StairMaker Add-On. By the way, I check a few version back, and Pen 23 was used even in ARCHICAD 16, possibly in even earlier versions.
The solution may be to set the desired values, create those Stairs and then save Favorites. Then later you will not have to create Stairs from scratch, you can simply apply Favorites.
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