I think I got ya.... Yes, leave the factory step and stand off alone and make 2 cuts in the post that end up ur total end length. Weld, DONT grind, and if it were me I would reinforce that spot with added plates welded on or if u had tubing the next size up/down that either slip inside the tube or sleeved over the outside....if u had tube to sleeve over u would have to grind the weld down but if u weren't sleeving it don't grind the weld... Point is I would reinforce the tubing. I'm a professional and I wouldn't trust a butt weld on thin tubing like that even if I did it myself....