Crossing the Peace Bridge into Canada at Buffalo with the NY EZpass,I was "up" charged from a class 4 to a class 5 combination of truck & trailer, adding $14.00 to the bridge charge. Filed an adjustment claim & they refunded the difference.
Interesting point - I was traveling with friends & their single axle trailer was also "up" charged a class. This happened to both of us on two separate crossings this year, one in July & one in September.
One might suspect that EZpass is trying to overcharge those that don't check their billing or don't bother to correct problems...