Siren doesn’t extend doorbell??!?

Language used online made it seem like the siren extends the doorbell chime. It looks like many are confused by this.

Our base station is on the second floor and we often don’t hear the doorbell chime so I bought sirens for the first and third floors. Once they arrived I realized they don’t extend the doorbell chime. 

I will be returning my sirens unless it’s added to the roadmap to enable them to chime on the doorbell.