This is normal. It's kind of a safety precaution - if you have only keyframes at your peaks, the interpolation inbetween might do strange things. Also it will already modulate the falloffs in a usable manner, which would be tricky otherwise. If the many keyframes bother you, you can always try The Smoother or manual deletion. Another easy way to "ignore" certain keyframes is using a simple clamp(min_value,max_value,input_value) expression.