A septal extension graft is a great technique that can achieve many things including derotation, tip projection changes, columellar length changes, and stability of the lower nose. It does not directly help with nasal valve issues, but when correcting valve issues with techniques like lateral crural strut grafts, it is important to have a strong central support like a SEG. It's also important to note that it's not just about the chosen technique, it's how you perform it for each specific case and in the combination with other techniques. These are some of the things that make rhinoplasty, especially revisions difficult. In revision cases we also have to consider that there is scar tissue and typically a lack of good cartilage support. This requires a lot of strengthening to get the desired shape and support. Although your question is fair, it is a very small part of the big picture for your Revision. I highly recommend scheduling at least a few quality consultations to discuss the overall desired shape and potential surgical plan. You can learn a lot more and compare the plans and photos. Good luck!