Can't always find a way to vent a 90. Or some just don't want them.
Around here, many or most jobs aren't permitted. Even if it is, probably won't be inspected. Many areas outside Indy itself have no licensing and permitting anyway. And with homeowners beating us down to the last dollar, b-vent seems to be one of the first things to go. I know our salesmen/owner rarely use it. If you do, you likely will be too high and lose the job. Sad but true.
Wow that's horrible, I honestly only see mid efficients when I'm tearing them out, and that isn't like any b-vent I have ever seen, plus up here you can't horizontally vent with b-vent, has to be stainless now, use a product called z-vent, very nice to work with but stupid expensive