A supplement is an update to the original repair estimate when additional damage is discovered during the repair process. Hidden damage — bent frames, damaged sensors, compromised structural components — is extremely common after a collision and not always visible during the initial inspection. Supplements are normal, legitimate, and necessary. They are submitted to your insurance company for approval. At HiStar, we document everything that drives a supplement so you and your insurer understand exactly what was found and why it needs to be fixed.