My EZ pass is set up for 2 axles. When not towing, I can zip thru any EZ pass lane. When towing anything, I have to go thru a manned booth where the transponder sets off a signal inside booth, toll taker punches in correct axles and away we go. If the EZ pass is set up for 4 axles, any time I wasn't towing anything I would have to go thru a manned booth to get correct billing (2 axles instead of 3 or more).
Was told that with my current set up with EZ pass (2 axle) and went thru the EZ pass lane could result in getting dinged big time for tolls. Guess bottom line is, if you don't want to mess w/ manned booths, get 2 passes (2 axle and 3 axles or more). Either way, your still getting the EZ pass toll discount.