Today I ran the following command. Based on the above articles, I should have had 0 results (I have never manually chnaged the autogrow settings for a volume), however I found 74 volumes that were using autosize-grow-threshold-percent settings higher than 85%. Some were 90%, some 92%, some 95%. There were 127 volumes at 85% as I expected.
Right, that's the exact list I've been using for years that's covered in the link in my initial post. The issue is that these percentages (in some cases) are different than they should be. Since posting this, I've discovered that resizing a volume doesn't also change the threshold. It stays the same based on the original volume size. Not intuitive at all but that's how it works. The only fix I know of is to audit volumes every so often and correct any that have changed.