Ring Pro ask for 16-22 volts. I have a 30 VDC. Any issues?

A little confused. (Not unusual) I have three doorbells on my house all terminating on the same centralized bell chime. Transformer putting out about 28vdc. Is this OK or do I need to replace it. Goes to a mechanical chime. Also, because it accepts three door bells there is a mess of wires. No markings on the chime, all wires are exactly the same bell chime wire. Anyone have an easy way to figure out front and transformer contacts? I have to do this ten feet in the air. Nothing is easy in life. There goes the "simple" , "20 minute installation"