CTS- The control of the speed and travel of the paddle is what will come AND keep you from rounding tips. You want to start the "Up and Forward" stroke at the choil and end at the Tip, Not roll off the end.
The roll off the end takes the tip Off (rounds it)
As for the knives not getting sharp - Simply, you are not apexing the the edge. IF (like me) you have a hard time detecting the burr then rely on completely removing the sharpie "Tick" Use Magnification.
Do not advance to the next paddle thinking "I'll get it sharp on this one" it should be thumb grabbing sharp after the 100 grit and then the edge just gets refined as you progress from there.