In the examples I looked at, you would run a rep scheme on ID for several weeks in a row as long as you were making the reps. When you are barely making the sets, switch to a lower rep scheme. Eventually you'll be doing singles and maybe once you'd do a 1RM. This is what I did and it worked well.
If you want to compare different rep schemes, you could use an estimated 1RM. Just remember that it's an estimate. It should trend upwards (and it would in your example). That's one way to tell that you're making progress.