I set the "boost" on my Prodigy P2 higher when I am on the freeway. My experience is just like yours with regards to feeling like the trailer is doing all of the braking in town and not enough on the freeway. By adjusting my controller from boost 1 around town to boost 2 or 3 on the freeway makes for a better towing experience. I do the same with my flatbed trailer when it is loaded heavy
Brent('85) & Lindsay('86) DDs('08 &'11)
'14 RAM Laramie 3500SRW CCLB Cummins/4x4/68RFE
-B&W Turnover Ball/Anderson Ultimate Aluminum
Toyhauler-'06 Forest River Sierra Sport F32
2001 Malibu Sunsetter VLX Wakeboat