I would follow the link above and apply what is relevant to you.
Sorry for my delayed response... life got in the way.
Your answer is NOT "correct". The link refers to CS6. I did not have a problem until CC2018.
Upon further investigation I found a bug in the program, which also explains why you thought the link would help:
- The free floating TRANSFORM panel you access from the Window dropdown works just like it always did... when I put my cursor in the X, Y, W or H and click an up or down arrow key it first rounds to the nearest .125" then increases or decreases .125" at a time (assuming the units are set to inches).
- The Transform section embedded in the new PROPERTIES panel does NOT work properly. It only goes up and down in 1" increments.
I am using Illustrator 22.0.1, so I do not know if this has been addressed in a patch, but it would be awesome if it was.