Actually, a strata lawyer will be able to quote chapter and verse on any precedents where the “uniformity” rule has failed to prevent owners from changing common property.
Also, reverse-cycle aircon can be allowed to change common property under a sustainability resolution, so it only requires a simple majority (not 75 percent) to get OC approval.
Perhaps warning the strata committee (via a lawyer) that they are backing themselves into a very expensive corner might avoid litigation altogether.