Punk and D of C have nailed it. In my experience the most assertive elder has his opinions listened to. That is human nature, I guess.
When the Presiding Overseer became the Co-ordinater it was meant to show that there was no superiority but in practice little changed . Mostly the COBE is the smartest one and has been appointed by the C.O. , so he takes charge.
In my last appointment, the PO and Service Overseer ruled the roost , a third elder always agreed with what they said, leaving me and another decent elder always out voted.