Ours is old also, probably makes it a Classic (white). It does have a sensitivity adjustment that I set about mid-point or lower.
My theory is that I only want the Brake Buddy to engage on a panic stop, normal stops aren't needed. For my use, proportional braking is useless. Ours has only engaged a couple of times in 60K miles of towing, both times I was glad I had it.
Denny, Connie & Shadow (former barn cat made good)
2000 Itasca Horizon, Cat 3126B, Freightliner Chassis