Trailair Flex Air Pin Box

My Trailair Tri-Glide pin box did a very good job of dampening up-and-down as well as front-to-back jerking, but after 10 years, it broke. I replaced it with a Trailair Flex Air pin box. Now after towing about 1000 miles with the Flex Air, it seems like it doesn't do much for front-to-back jerking.

Does anyone else have the same feeling about the Flex Air?