Seems like there's an extra division by 10 somewhere, because at 2% quality, for instance, I'm seeing only a 0.2% (.0002) chance to upgrade to Normal->Uncommon. Shouldn't it be 2%?

Currently you need 1000% quality to get a 100% chance to upgrade the first level, which seems off by an order of magnitude.

I'm on default settings, and I did notice you can't set the chance to 1 there, which would let me correct this issue.

2.1 or 2.0?

2.1

I'll look at what changed with quality in 2.1.

FWIW I just downloaded the mod and changed the settings values by multiplying them by 10x, e.g.

  {
    type = "double-setting",
    name = "uncommon-chance",
    setting_type = "startup",
    minimum_value = .00001,
    default_value = 1, <=== this was .1, now 1
    maximum_value = 1, <=== this was .1, now 1
    order = "fa"
  },
  {
    type = "double-setting",
    name = "rare-chance",
    setting_type = "startup",
    minimum_value = .00001,
    default_value = .7, <=== this was .07, now .7
    maximum_value = 1, <=== this was .1, now 1
    order = "fb"
  },

And this shows the expected values. A quality of 2% in a machine results in 2% chance to upgrade Normal -> Uncommon.

If you've got a github for this I'd be happy to submit a PR, I can also look into how to mask this complexity from users of the mod - i.e. not exposing the fact that quality must be 10x'ed in 2.1 from what's configured in settings.

Gonna be a bit more than that. I'm debating if I even want to do this.

if I even want to do this

What do you mean? The fix, or the mod as a whole?

The fix works, it just looks unintuitive.

I forked this to fix a bug that it gave me with the outer rim, not to have something else to maintain. (:
I have like 3-4 other things I need to (finally) finish, I'm removing the 2.1 version.

Fair enough! I did a bit of Rimworld modding, and I know how much less fun / more work maintenance can be :) I was a steeper quality user which is what drew me to your mod, since you were so quick to update to 2.1.

Best of luck!

My current view on this is that if I can't do a quick fix (I clearly can't) then this is not what I want to spend my time on.

Thank you!