Yes, what you tend to was exactly the good intention by the dev in the first place.

As to your finding in practice, my answer is "I never really know".

My biggest problem here is that I usually don't pay attention to most of my prisoners unless some are doing or have just done something significant.

Unlike RimWorld, there are too many little guys keep coming to and leaving from my prison.

The lead dev of RimWorld believes the max number of characters should be only 24. If more than that, a player will have much difficulty in remembering and tracking and, more importantly, caring about characters.

In PA, I sometimes actively locate and track a few special prisoners. In most cases, dangerous ones.

These guys are not the target of the "Cell Room Grading" mechanism. Instead of punishing them when they misbehave and moving them to better rooms when they behave, I just put them in Max-Sec wing, completely separated from the rest of inmates.

As to less troublesome prisoners, whether they have hope about moving to better rooms seem unimportant to me.

Most of prisoners will be released after some days. I don't think it worth my care about whether and when to change their rooms.

I'd rather working on increase of parole rate.

I see your point, but for some reason I have a hard time giving up on the cell rating system. I always think "maybe this time..." like a gambling addiction, LOL. I don't tend to pay attention to specific inmates either, I barely even read rapsheets. but the cell grading system would be a wonderful way of organizing troublemakers if it worked. I'm surprised no one has made a mod that fixes it. The modding community for rimworld is so robust and healthy but the one for paradox is a bit anemic.

the modding mechanism of PA is not very good. I don't think anyone can mod about cell grading system or some other systems.

That explains it. Thats too bad. It's a good game that could be great if they would just fix a few things. But they're more interested in making DLC they can make more money off of.