Hal,
You really set up a challenge for your self to improve your shooting skills. I like to do something a little more difficult each time I shoot so I can shoot better and make it a bit more interesting.
Consider this, each time you shoot at a target you determine if it is a pass of fail. Now after you have shot at 10 different targets, you can look at them as a "group" to determine your over-all consistency. So if 7 out of 10 pass and 3 fail, you now know you pass rate is, obviously, 70%. Thus you now know your overall performance level based on that group of 10 individual tests.
You have set up an interesting way for a shooter to challenge and improve himself in a fun kind of way. And if you use the replacement dots on a Shoot&See target, you can use the same target 12 times more!
Oh, and one more question, is that soup can at 300 yards Chicken Noodle or Cream of Chicken?