The attic vents have been around for several years on SOB's ... I dunno when Cedar Creek started installing them. A fair amount of moisture can form in-between the roof and ceiling, so the vents do serve a purpose.
A plumber once told me you have to have air behind sewage or in other words a sewer line cannot flow through or might suck the water out of the trap in a siphon effect uless air can get behind the sewage. So is it that there has to be a tank where there is a vent or can the vent sometimes be necessary to allow that branch of the sewer system to FLOW to the tank?