The term to be precise about is license versus assignment. A license is permission to use the work on stated terms, which is what your agreement grants, and a listing-term license is common in real estate media. An assignment, sometimes sold as a buyout or full rights, transfers ownership of the copyright itself and has to be in writing and signed. In the US, copyright starts with the creator unless there's a signed transfer or a work-made-for-hire arrangement that qualifies, and whether your particular agreement does either of those things is a question for an attorney rather than a forum.
So the brokerage's case study sits outside your license as written. That's normally a $200 to $500 conversation with the photographer, not a fight, and the same add-on usually covers reuse at a future relisting. Ask for the extended license to name the brokerage too, since they're the ones publishing.
@anchor, the reason people don't always buy the broadest rights up front is that they're paying for a use they may never make. A seller who lists once and closes gets nothing from perpetual rights. Sellers of land and development sites, where the same parcel may be marketed in phases for years, are exactly the ones who should price the buyout on day one.
Separately, check what your MLS requires. Many MLS rules make the person submitting a photo warrant they have the right to license it onward to the MLS, so a license limited to "you, for this listing" can end up conflicting with the paperwork you sign at upload. Rules on that vary by MLS.