The Mitel systems have 3 ring modes.
Day - for regular business hours call treatments
Night 1 - for regular off hour call treatments
Night 2 - for irregular off hour call treatments
Most of the sites I have only use 2 ring modes. In these cases, I program the Night 2 to be exactly like the Night 1 so that if someone screws up, calls will still be handled the same way.
I usually use the Night 2 for cases where a backup person handles lunch time calls or the customer wants to forward immediately all calls to an answering service or Auto Attendant, you know, something out of the ordinary.
The three ring modes just give flexibility.
**************************************
My Biggest problem is that I almost always believe what I tell myself.