But why?

About three years ago, the six elevators in the office building where I work were upgraded to be accessible for the visually-impaired. As part of the upgrade, the elevators now verbally announce the floor that they’re stopping on. Except… Some of them announce “Floor ten” and others “Tenth floor.” All six elevators are in one cluster and, in fact, they have common software as they have a system where you select your destination floor and are directed to a specific one of the six. So, why in the heck does the verbal announcement differ? Inquiring minds want to know. Drives me crazy.