For what it's worth, I've had a very similar experience....like you, I'm on half the dose of what the doctor suggested for a beta blocker (I'm on a tiny 5mg of Nadolol...tried the 10 mg dose they suggested for several days and concluded the side effects at that dosage outweighed the benefits). Like you too, I notice that I get fewer jumps in heart rate and in my case, fewer bp jumps as well, so it helped with the discomfort that came along with those, but it didn't help the dizziness and other symptoms at all. I'm no expert on beta blockers, but I'm assuming that's because beta blockers are only designed to lower your heart rate and blood pressure, not treat whatever causes the dysautonomia itself. Our bodies presumably still have troubles regulating blood flow to our heads and all the other places that need blood, and that means we still have symptoms.