Very suspicious that the trailer brakes are not doing their share as has been mentioned above. If manual actuation of the trailer brakes with the controller on max setting does not pull the speed down fast, they're probably not doing their share. Does the Prowler have Lippert 4400 lb. axles? I had those on our Puma and found them to be extremely weak. I improved the voltage to the axles by replacing the one 14 gauge brake cable with two 12 gauge cables. Also, good chance the brakes are out of adjustment because it only takes a few thousand miles to need adjustment. They should be tight enough that the wheel will spin only one turn when given a spin by hand. If that doesn't do the trick, then it will be time for larger hubs with more aggressive linings, which is what I'm breaking in right now. Also switched to Dexter.