1st and 2nd floor deck dimensions are different???

[Bill B]

David, Kat - thank you both very much. I now understand my mistake. I simply drew deck railings instead of creating a wall and then changing it to a railing style. It looks fine now. I'm learning :-)
I still do not understand how the 2nd floor dimensions can be slightly different from the first if you derive the 2nd from the 1st. cheers, Bill B.