Tom,
Thank you for explaining what ciliary lock-up is in briefer words.
But you might want to consider the following:
When working with plus lenses or under prescription on close up distance, there's a way to gain more improvements and it implies, after having "warmed up" your eyes for about 20 minutes wearing the plus or under prescription, to back up the furthest you can while the letters are still readable. The letters should not be sharp but shouldn't be blurred either, it's the point where you can barely read them. Blink a few times and then, staring at one part of a word or a letter, without blinking, you allow your eyes to focus the image. It takes around 15 seconds for the eyes (and brain) to focus the image and then you want to stare at it the most you can without blinking (a.k.a without straining; that's why the eyes need to be warmed up). This keeps the ciliary where it has to be for it to focus. The "exercise" should not be done more than 10-15 minutes the first times so we don't strain our eyes.
Now, going back to the ciliary lock-up, I believe the exercise justifies staring at one distance for some time and shouldn't be confused with lock-up because you're still working on focusing at a range beyond what you might have considered "possible." However, for the rest of the times, while focusing up close I think that what you say is very important because once the ciliary locks-up the rest of day it becomes harder to keep focusing at longer distances.
Thank you Tom for the insights,
Chris
PS: The exercise I mention is a very rough summary of one of the installments that Alex Frauenfeld shares, so the credit goes to him.