(The one thing about Mike's plan I don't get it that tolls paid will be subtracted from the congestion pricing.)

I think one of the things they are trying to get away from is people driving out of their way to the free bridges (I'll admit I do it myself; otherwise it would be the Brooklyn-Battery every time, though I don't drive to Manhattan just through it.).

If they make people pay a BBT toll and congestion pricing, they'd be paying twice -- and they'd really want to drive to the Brooklyn Bridge.