Is the toilet flange too high off the ground

I found this 2 part video on YouTube that helped me understand what to do.

part1 part2

I ended up cutting off the top of the flange with a PVC pipe cable saw. I then used a mini hacksaw to cut some segments into the fitting and wedged the pieces out. After removing 2 small parts of the ring, the rest just wedged right out without much effort. I cut down the pipe to be flush with the floor using a pull saw. I put a level down and found the concrete was not level around the pipe. I used a rub brick and the mini hacksaw, which I could angle to cut the inside of the pipe, to get the pipe and surrounding concrete truly level with the rest of the floor. This took a while.

When I finally got it level, I put in a Twist N Set Closet Flange. I drilled 4 pilot holes and put in concrete screws. The toilet is now level and not going anywhere. Now I just have to fix my guest bathroom which has the exact same problem. At least I got a good deal on the house.

The bottom of the flange needs to be sitting flush with (or not more than 1/8" above) the finished floor or else the toilet will rock. The flange should be fastened to the floor. Dry fit the toilet to make sure it doesn't rock. If it does rock, use shims to prevent rocking - just tightening the bolts probably will not stop the rocking but will risk cracking the toilet or breaking the flange.