I know you're probably joking, but I think this is an important point, so I want to say - yes!

If I ask you to go without food for seven days, without really giving you a reason, but just saying it would increase my respect for you or something -- and you refused, would that be the fault of your poor self-control? No, it would be a reasonable cost-benefit decision.

On the other hand, when we take something like addiction that people commonly claim to have no self-control over - well, if you put a gun to someone's head and threatened to kill them if they had another drink of alcohol, then as long as you can continue enforcing the threat, suddenly self-control isn't so much of an issue.

Now all of this is complicated by hyperbolic discounting and psychodynamics and so on, but at some point, "self control" is a matter of how much of a reward or punishment you're expecting. So if you keep that on there, I predict you're measuring two things. First of all, how much people care about a worksheet - such that if this "leveling" thing became wildly popular and prospective employers asked you your level before hiring that would change motivation. And how annoying it is for you to concentrate at that level (eg ADHD people would have a much harder time; other people might have more or less natural concenration issues) - such that if you chose a different "self control" task like going without food for a certain amount of time, or squeezing a lever at a certain strength, you would get different results.

In either case, I don't think measuring "self-control" as a real variable across people is on a firm philosophical footing.